Application of evaporative cooling on the condenser of window-air-conditioner

International Nuclear Information System (INIS)

Hajidavalloo, Ebrahim

2007-01-01

Reduction of energy consumption is a major concern in the vapor compression refrigeration cycle especially in the area with very hot weather conditions (about 50 deg. C), where window-air-conditioners are usually used to cool homes. In this weather condition performance of air condenser window-air-conditioners decrease sharply and electrical power consumption increase considerably. These problems have activated the research programs in order to improve the performance of window-air-conditioners by enhancing heat transfer rate in the condenser. In this article, a new design with high commercialization potential for incorporating of evaporative cooling in the condenser of window-air-conditioner is introduced and experimentally investigated. A real air conditioner is used to test the innovation by putting two cooling pads in both sides of the air conditioner and injecting water on them in order to cool down the air before it passing over the condenser. The experimental results show that thermodynamic characteristics of new system are considerably improved and power consumption decreases by about 16% and the coefficient of performance increases by about 55%

Application of evaporative cooling on the condenser of window-air-conditioner

Energy Technology Data Exchange (ETDEWEB)

Hajidavalloo, Ebrahim [Shahid Chamran University, Department of Mechanical Engineering, Golestan St., Ahwaz, Khoozestan 61355 (Iran, Islamic Republic of)]. E-mail: hajidae_1999@yahoo.com

2007-08-15

Reduction of energy consumption is a major concern in the vapor compression refrigeration cycle especially in the area with very hot weather conditions (about 50 deg. C), where window-air-conditioners are usually used to cool homes. In this weather condition performance of air condenser window-air-conditioners decrease sharply and electrical power consumption increase considerably. These problems have activated the research programs in order to improve the performance of window-air-conditioners by enhancing heat transfer rate in the condenser. In this article, a new design with high commercialization potential for incorporating of evaporative cooling in the condenser of window-air-conditioner is introduced and experimentally investigated. A real air conditioner is used to test the innovation by putting two cooling pads in both sides of the air conditioner and injecting water on them in order to cool down the air before it passing over the condenser. The experimental results show that thermodynamic characteristics of new system are considerably improved and power consumption decreases by about 16% and the coefficient of performance increases by about 55%.

Mold contamination of automobile air conditioner systems.

Science.gov (United States)

Kumar, P; Lopez, M; Fan, W; Cambre, K; Elston, R C

1990-02-01

Eight cars belonging to patients who were found to have exacerbation of allergic rhinitis and bronchial asthma after turning on the air conditioner in their cars were examined. Mold concentrations inside the passenger compartment with the a/c turned off and at different climate control settings were lower than concentrations in the outside air. After turning on the air conditioner to "Max", cultures obtained at various intervals revealed that mold concentrations decreased significantly with time. Furthermore, placement of a filter at the portal of entry of outside air significantly reduced the mold concentration in the passenger compartment.

[Gohieria fusca found in dust of air-conditioner filters].

Science.gov (United States)

Qiang, Chai; Xiao-Dong, Zhan; Wei, Guo; Chao-Pin, Li

2017-09-25

To investigate the pollution status of Gohieria fusca in the air conditioner-filters of different places in Wuhu City. The dust samples were collected from the filters of air-conditioners in dining rooms, shopping malls, hotels and households between June and September, 2013, and G. fusca was detected in the dust samples. There were 430 dust samples collected and 98 were G. fusca positive with the breeding rate of 22.79%. The difference of breeding rates of G. fusca were statistically significant among the different places ( χ 2 =18.294, P air-conditioner filters in Wuhu City gravely.

10 CFR 431.92 - Definitions concerning commercial air conditioners and heat pumps.

Science.gov (United States)

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Definitions concerning commercial air conditioners and... PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Commercial Air Conditioners and Heat Pumps § 431.92 Definitions concerning commercial air conditioners and heat pumps. The following definitions apply...

75 FR 72739 - Compliance Testing Procedures: Correction Factor for Room Air Conditioners

Science.gov (United States)

2010-11-26

...: Correction Factor for Room Air Conditioners AGENCY: Office of the General Counsel, Department of Energy (DOE... air conditioners. The petition seeks temporary enforcement forbearance, or in the alternative, a... procedures for room air conditioners. Public comment is requested on whether DOE should grant the petition...

Control Technologies for Room Air-conditioner and Packaged Air-conditioner

Science.gov (United States)

Ito, Nobuhisa

Trends of control technologies about air-conditioning machineries, especially room or packaged air conditioners, are presented in this paper. Multiple air conditioning systems for office buildings are mainly described as one application of the refrigeration cycle control technologies including sensors for thermal comfort and heating/ cooling loads are also described as one of the system control technologies. Inverter systems and related technologies for driving variable speed compressors are described in both case of including induction motors and brushless DC motors. Technologies for more accurate control to meet various kind of regulations such as ozone layer destruction, energy saving and global warming, and for eliminating harmonic distortion of power source current, as a typical EMC problem, will be urgently desired.

Need Analysis for Air Conditioners in Public Sector of Surabaya City Government

Directory of Open Access Journals (Sweden)

Dwiarti Larasputri

2017-01-01

Full Text Available In typical buildings, air conditioners have the biggest percentage in energy consumption among all sectors. It makes a good management for air conditioners is needed and important in order to use the energy efficiently. Having a very hot and humid weather, it gives impact that most of buildings in Surabaya installed air conditioners, including Surabaya City Government office buildings. However, there is no regulation nor guidance how to manage air conditioners in Surabaya City Government, while Surabaya itself has a goal to become a green-eco city. Then, the existing condition of air conditioners usage in Surabaya Government units (SKPDs is evaluated. The evaluation resulted that most of air conditioners were over capacity and not all of them were efficient in energy consumption. Therefore, a need analysis is required to help Surabaya City Government managing its air conditioners better. By applying two different concepts, one is based on the architectural view and another one is based on green building criteria, the existing condition is analyzed and two procedures of need analysis are produced. The procedures can be implemented for two different conditions of office building rooms in Surabaya City Government.

[Research on dust mite allergen gathered from filters of air-conditioners].

Science.gov (United States)

Zhan, Xiao-dong; Wu, Hua; Hu, Hui-min; Li, Chao-pin

2015-12-01

To discuss the relation between the dust mite allergen (Der) in air-conditioner filters and the asthma attack. The dust samples were collected from the filters of air-conditioners in dining rooms, shopping malls, hotels and households, respectively. The concentrations of Der f 1 and Der p1 were detected by ELISA, and the dust mite immune activities were determined by dot-ELISA. The concentrations of Der f 1 in the dining rooms, shopping malls, hotels and households were 1.52, 1.24, 1.31 µg/g and 1.46 µg/g respectively, and the concentrations of Der p 1 were 1.23, 1.12, 1.16 µg/ g and 1.18 µg, respectively. One hour after the running of air-conditioners, the concentrations of Der f 1 and Der p 1 in the air were higher than those before the running of air-conditioners, and the differences were significant (P air-conditioners in domestic houses in Wuhu City, and the allergens can induce asthma.

Ventilating Air-Conditioner

Science.gov (United States)

Dinh, Khanh

1994-01-01

Air-conditioner provides ventilation designed to be used alone or incorporated into cooling or heating system operates efficiently only by recirculating stale air within building. Energy needed to operate overall ventilating cooling or heating system slightly greater than operating nonventilating cooling or heating system. Helps to preserve energy efficiency while satisfying need for increased forced ventilation to prevent accumulation of undesired gases like radon and formaldehyde. Provides fresh treated air to variety of confined spaces: hospital surgeries, laboratories, clean rooms, and printing shops and other places where solvents used. In mobile homes and portable classrooms, eliminates irritant chemicals exuded by carpets, panels, and other materials, ensuring healthy indoor environment for occupants.

Analysis on a hybrid desiccant air-conditioning system

International Nuclear Information System (INIS)

Jia, C.X.; Dai, Y.J.; Wu, J.Y.; Wang, R.Z.

2006-01-01

Hybrid desiccant-assisted preconditioner and split cooling coil system, which combines the merits of moisture removal by desiccant and cooling coil for sensible heat removal, is a potential alternative to conventional vapor compression cooling systems. In this paper, experiments on a hybrid desiccant air-conditioning system, which is actually an integration of a rotary solid desiccant dehumidification and a vapor compression air-conditioning unit, had been carried out. It is found that, compared with the conventional VC (vapor compression) system, the hybrid desiccant cooling system economizes 37.5% electricity powers when the process air temperature and relative humidity are maintained at 30 o C, and 55% respectively. The reason why the hybrid desiccant cooling system features better performance relative to the VC system lies in the improvement brought about in the performance of the evaporator in VC unit due to desiccant dehumidification. A thermodynamic model of the hybrid desiccant system with R-22 as the refrigerant has been developed and the impact of operating parameters on the sensible heat ratio of the evaporator and the electric power saving rate has been analyzed. It is found that a majority of evaporators can operate in the dry condition even if the regeneration temperature is lower (i.e. 80 o C)

Air conditioner

International Nuclear Information System (INIS)

Sato, Masaaki

1993-01-01

The present invention provides an air conditioner which can prevent an undesirable effects on a human body due to radon daughter nuclides in a closed space. That is, the concentration of the radon daughter nuclides in the air in the closed space is continuously measured. A necessary amount of ventilation air is determined based on the measured concentration to generate control signals. External air is introduced into the closed space by the generated control signals. With such procedures, necessary amount of external air is taken from the atmospheric air which can be regarded to have the radon daughter nuclide concentration substantially at zero, thereby enabling to reduce the concentration of the radon daughter nuclides in the closed space. As a result, undesired effects on the human body due to the radon daughter nuclides staying in the closed space can be prevented. According to simulation, the radon daughter nuclides are rapidly decreased only by ventilation only for three times or so in one hour. Accordingly, ventilation is extremely effective and convenient means as a countermeasure for the radon daughter nuclides. (I.S.)

Comparison of desiccant air conditioning systems with different indirect evaporative air coolers

International Nuclear Information System (INIS)

Pandelidis, Demis; Anisimov, Sergey; Worek, William M.; Drąg, Paweł

2016-01-01

Highlights: • A numerical study of desiccant air conditioning systems is presented. • The ε-NTU model is used for the analysis. • Different arrangements of the desiccant systems were compared. • The systems were compared under different operating conditions. - Abstract: This paper presents a numerical analysis of three desiccant air-conditioning systems equipped with different indirect evaporative air coolers: (1) the cross-flow Maisotsenko cycle heat and mass exchanger (HMX), (2) the regenerative counter-flow Maisotsenko cycle heat and mass exchanger and (3) the standard cross-flow evaporative air cooler. To analyze the desiccant wheel and the indirect evaporative air coolers, the modified ε-NTU-model was used. The simulations were performed under assumption that the desiccant wheel is regenerated with air heated to relatively low temperature values (50–60 °C), which can be produced with solar panels in typical moderate climatic conditions. It was established that the main advantage of the presented solutions is that they can provide comfort conditions even with less effective dehumidification. The different systems were compared under variable selected operational factors (i.e. inlet air temperature, humidity and regeneration air temperature). The analysis allowed establishing the advantages and disadvantages of presented solutions and allowed estimating their application potential.

Residential air-conditioner usage in China and efficiency standardization

International Nuclear Information System (INIS)

Wu, Jianghong; Liu, Chaopeng; Li, Hongqi; Ouyang, Dong; Cheng, Jianhong; Wang, Yuanxia; You, Shaofang

2017-01-01

Determining the real energy consumption and usage pattern of a room air-conditioner (RAC) are important issues from the point of view of both RAC design and evaluation of its energy efficiency. An air-conditioner's running time is fundamental data for the calculation of SEER and APF values. Therefore, in 2010, a nationwide investigation of RAC usage was conducted and 400 selected air-conditioning-units were monitored for a full year to obtain data on their cooling and heating usage. Two running time curves (cooling and heating) were obtained for the air-conditioners as a function of outdoor air temperatures using statistical analysis. The results show that the 27–30 °C temperature range accounts for more than 52% of the cooling time. Conversely, the 0–8 °C temperature range is associated with more than 75% of the heating time. The research presented in this paper has significantly contributed to China's new variable-speed RAC efficiency standard (GB21455-2013). It also has far-reaching implications for both the air-conditioner industry and energy policy in China due to its different method of calculating energy efficiency. - Highlights: • A nationwide survey to realize China's residential air-conditions usage behaviors. • Air-conditioner running time-environment temperature curves are obtained. • The peak heating demand and peak cooling demand happen at 28 °C and 4 °C, respectively. • The temperature of 27 °C–30 °C accounts for over 52% refrigeration time. • The temperature of 0 °C–8 °C occupies more than 75% heating time.

Viewpoint Mitigation of emissions through energy efficiency standards for room air conditioners in Malaysia

International Nuclear Information System (INIS)

Mahlia, T.M.I.; Masjuki, H.H.; Saidur, R.; Amalina, M.A.

2004-01-01

Malaysian economy has grown rapidly in the last two decades. This growth has increased the ownership of household electrical appliances including room air conditioners. The number of users of air conditioners is predicted to grow dramatically in Malaysian households in the future. To reduce energy consumption in the residential sector, the Malaysia Energy Commission is considering implementing minimum energy efficiency standards for room air conditioners in early 2004. This paper attempts to predict the potential mitigation of emissions through energy efficiency standards for room air conditioners in Malaysia. The calculations were based on the growth of room air conditioners ownership data in Malaysian households. The study found that the energy efficiency standards for room air conditioners would mitigate a significant amount of emissions in this country

16 CFR 305.12 - Labeling for central air conditioners, heat pumps, and furnaces.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Labeling for central air conditioners, heat... (âAPPLIANCE LABELING RULEâ) Required Disclosures § 305.12 Labeling for central air conditioners, heat pumps, and furnaces. (a) Layout. All energy labels for central air conditioners, heat pumps, and...

Evaluation of environmental and physiological factors of a whole ceiling-type air conditioner using a salivary biomarker

Energy Technology Data Exchange (ETDEWEB)

Tahara, Yusuke; Yamaguchi, Masaki [Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Morito, Naomi; Nishimiya, Hajime; Yamagishi, Hideyuki [Asahi Kasei Homes Corporation, R and D Laboratories, 2-1 Samejima, Fuji, Shizuoka 416-8501 (Japan)

2009-06-15

In order to improve environmental condition such as humidity and airflow in living spaces, a whole ceiling-type air conditioner is proposed. This novel air conditioner exhaust dispersed airflow from the whole ceiling by using a 3-dimensional knit fabric. The purpose of this paper is to reveal the effects when controlling humidity and airflow using the whole ceiling-type air conditioner compared to a commercialized concentrated exhaust air conditioner (normal-type air conditioner) under the same temperature. Salivary {alpha}-amylase activity (SAA) was used as an index of sympathetic nervous activity. An acute experiment for a 15 min period was conducted using 12 healthy young female adults. No significant differences in room and skin temperatures were observed between the whole ceiling-type air conditioner and the normal-type air conditioner. The whole ceiling-type air conditioner showed 11.1% lower humidity than the normal-type air conditioner. The whole ceiling-type air conditioner showed one-thirteenth the airflow of the normal-type air conditioner. As a result, the PMV of the whole ceiling-type air conditioner was more comfortable level than the normal one. Moreover, subjective evaluation questionnaire revealed a significant difference was observed in wind perception (windy). The SAA of subjects under the whole ceiling-type air conditioner showed significantly low values compared with the normal-type air conditioner. It was found that the subject's sympathetic nervous activity has been inactivated under the conditions of the whole ceiling-type air conditioner. Thus, it was revealed that the whole ceiling-type air conditioner provides a more comfortable air environment by reducing physical stimulations to humans. (author)

Performance assessment and transient optimization of air precooling in multi-stage solid desiccant air conditioning systems

International Nuclear Information System (INIS)

Gadalla, Mohamed; Saghafifar, Mohammad

2016-01-01

Highlights: • Studying three two-stage solid desiccant cooling systems using Maisotsenko cooler. • Proposing precooling to improve two-stage desiccant systems’ COP for humid climates. • Performing transient analysis for a two-stage solid desiccant cooler in UAE. • Optimizing daily performance of a two-stage solid desiccant cooler for UAE. - Abstract: Renewable energy is one of the most promising solutions to both energy and global warming crisis. Energy consumption can be minimized considerably by utilizing solar energy in air conditioning systems operation. One of the popular solar air conditioning technologies is desiccant air conditioning. Nonetheless, conventional desiccant air conditioning systems have a relatively low coefficient of performance (COP). In consequence, two-stage desiccant air-conditioning systems are proposed to improve desiccant air conditioning systems’ COP. Moreover, a recently commercialized cooling method named Maisotsenko cooling cycle which is capable of cooling air near to its dew point temperature is considered to be integrated within the proposed multi-stage desiccant cooling systems. In this paper, three new two-stage desiccant air conditioning systems incorporating Maisotsenko cooling cycle are proposed and investigated in details for hot and humid climates such as UAE. Furthermore, air precooling is considered to improve two stage desiccant air conditioning systems’ COP. Moreover, full transient analysis and optimization are carried out in UAE within June–October. The proposed system can minimize the required solar heating during noon time as the ambient air dry bulb temperature rises. Average COP of the system during electricity load peak hours (10:00–14:00) for all five considered and combined months is 1.77. Average rate of heat input required to operate the system and average building cooling load are determined to be 100.3 kW and 46.2 kW, respectively. Therefore, system average COP is computed to be 0.46.

77 FR 28519 - Test Procedure Guidance for Room Air Conditioners, Residential Dishwashers, and Residential...

Science.gov (United States)

2012-05-15

... Guidance for Room Air Conditioners, Residential Dishwashers, and Residential Clothes Washers: Public... procedures for room air conditioners, residential dishwashers, and residential clothes washers. DATES: DOE...'s existing test procedures for residential room air conditioners, residential dishwashers, and...

16 CFR Appendix E to Part 305 - Room Air Conditioners

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Room Air Conditioners E Appendix E to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC ACTS OF CONGRESS RULE... Appendix E to Part 305—Room Air Conditioners Range Information Manufacturer's rated cooling capacity in Btu...

Ventilation-air conditioner system in nuclear power plant

International Nuclear Information System (INIS)

Kubota, Ryuji; Sugisaki, Toshihiko.

1989-01-01

This invention concerns a ventilation-air conditioner system which enables, upon occurrence of accidents in a nuclear power plant, continuous operation for other adjacent nuclear power plants with no effect of accidents. Air supply system and exhaust system are operated during usual operaiton. If loss of coolants accidents should occur in an adjacent nuclear power plants, operation is switched from ventilation operaiton to the operation of re-cycling system based on an AND logic of three signals, that is, a pressure HIGH signal for the reactor container, a water level LOW signal for the reactor and a radioactivity signal of the ventilation-air conditioner sytem on the side of air supply in the nuclear power plant. Thus, nuclear reactor buildings of the nuclear power plant are from the external atmosphere. Therefore, the radioactivity HIGH signal for switching to the emergency air conditioner system of the nuclear power plant is not actuated due to the loss of coolant accidents in the adjacent nuclear power plant. In addition, since the atmospheric temperature in the nuclear reactor building can be maintained by a cooling device disposed to the recycling system, reactor shutdown can be prevented. (I.S.)

Active Participation of Air Conditioners in Power System Frequency Control Considering Users’ Thermal Comfort

Directory of Open Access Journals (Sweden)

Rongxiang Zhang

2015-09-01

Full Text Available Air conditioners have great potential to participate in power system frequency control. This paper proposes a control strategy to facilitate the active participation of air conditioners. For each air conditioner, a decentralized control law is designed to adjust its temperature set point in response to the system frequency deviation. The decentralized control law accounts for the user’s thermal comfort that is evaluated by a fuzzy algorithm. The aggregation of air conditioners’ response is conducted by using the Monte Carlo simulation method. A structure preserving model is applied to the multi-bus power system, in which air conditioners are aggregated at certain load buses. An inner-outer iteration scheme is adopted to solve power system dynamics. An experiment is conducted on a test air conditioner to examine the performance of the proposed decentralized control law. Simulation results on a test power system verify the effectiveness of the proposed strategy for air conditioners participating in frequency control.

ENERGY STAR Certified Room Air Conditioners

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Room Air Conditioners that are effective as of...

The life cycle rebound effect of air-conditioner consumption in China

International Nuclear Information System (INIS)

Liu, Jingru; Sun, Xin; Lu, Bin; Zhang, Yunkun; Sun, Rui

2016-01-01

Highlights: • Develop a life cycle rebound effect model. • Assess the life cycle rebound effect of Chinese room air conditioners. • Conduct a questionnaire to assess the consumption behavior of Chinese room air conditioners. • Rebound effect should be considered by energy policy makers. - Abstract: Governments worldwide are attempting to reduce energy consumption and environmental pollution by confronting environmental problems and adopting more energy-efficient products. However, because of the rebound effect, energy-saving targets cannot always be fully achieved, and sometimes greater energy consumption is generated. Research on the rebound effect from the perspective of industrial ecology considers not only direct energy consumption but also its life cycle negative impacts on the environment with China’s rapid economic development and simultaneously improving quality of life, the ownership of room air conditioners (RACs) has increased more than three hundred times, and air conditioners’ energy consumption has increased one thousand times over the last twenty years. The Air Conditioner Energy Efficiency Standard is one of the most important measures in China for reducing the amount of energy consumed by RACs. This paper introduces a life cycle based method to estimate the rebound effect of Chinese RACs consumption. This model provides a product’s life-cycle view to assess the rebound effect, considering the contribution of both producer and consumer. Based on the established life cycle rebound effect model, we compared urban household RAC consumption behaviour before and after the launch of the Air Conditioner Energy Efficiency Standard. A rebound effect in RAC consumption was found that there was a longer daily usage period in the household as air conditioner efficiency levels improved. The life cycle rebound effect of household air-conditioner consumption was calculated to be 67%. The main conclusion obtained from this study is that policies and

77 FR 8178 - Test Procedures for Central Air Conditioners and Heat Pumps: Public Meeting

Science.gov (United States)

2012-02-14

.... EERE-2010-BT-TP-0038] Test Procedures for Central Air Conditioners and Heat Pumps: Public Meeting... methodologies and gather comments on testing residential central air conditioners and heat pumps designed to use... residential central air conditioners and heat pumps that are single phase with rated cooling capacities less...

Capacity modulation of an inverter-driven multi-air conditioner using electronic expansion valves

International Nuclear Information System (INIS)

Choi, J.M.; Kim, Y.C.

2003-01-01

An inverter-driven multi-air conditioner provides the benefits of comfort, energy conservation and easy maintenance. Recently, the multi-air conditioner has been employed in small and medium-sized buildings. However, the performance data and control algorithm for multi-air conditioners are limited in literature due to complicated system parameters and operating conditions. In the present study, the performance of an inverter-driven multi-air conditioner having two indoor units with electronic expansion valves (EEV) was measured by varying indoor loads, EEV opening, and compressor speed. Based on the experimental results, the operating characteristics and capacity modulation of the inverter-driven multi-air conditioner are discussed. As a result, it is suggested that the superheats for both indoor units have to be maintained around 4 o C by utilizing the EEVs in this system, and consequently, the compressor speed needs to be adjusted to provide optimum cooling capacity for each indoor unit

Research on a Micro-Grid Frequency Modulation Strategy Based on Optimal Utilization of Air Conditioners

Directory of Open Access Journals (Sweden)

Qingzhu Wan

2016-12-01

Full Text Available With the proportion of air conditioners increasing gradually, they can provide a certain amount of frequency-controlled reserves for a micro-grid. Optimizing utilization of air conditioners and considering load response characteristics and customer comfort, the frequency adjustment model is a quadratic function model between the trigger temperature of the air conditioner compressor, and frequency variation is provided, which can be used to regulate the trigger temperature of the air conditioner when the micro-grid frequency rises and falls. This frequency adjustment model combines a primary frequency modulation method and a secondary frequency modulation method of the energy storage system, in order to optimize the frequency of a micro-grid. The simulation results show that the frequency modulation strategy for air conditioners can effectively improve the frequency modulation ability of air conditioners and frequency modulation effects of a micro-grid in coordination with an energy storage system.

Strategies for reducing the environmental impacts of room air conditioners in Europe

International Nuclear Information System (INIS)

Grignon-Masse, Laurent; Riviere, Philippe; Adnot, Jerome

2011-01-01

In Europe, buildings tend to be equipped with individual air conditioners, which constitute a fast growing electrical end-use. In this context, this study aims to assess the environmental impacts of European individual air conditioners and to analyse policy strategies to reduce these impacts. After analysing the European context concerning individual air conditioners, the environmental impacts of European air conditioners are assessed using a Life Cycle Analysis approach. The following step consists in studying, both technically and economically, different improvement options aiming at reducing the environmental impacts of these appliances. These results, obtained at the product level, are then generalised at the European level and different policy measures are defined and analysed. The main conclusion is that the implementation of a Minimum Energy Performance Standard based on Least Life Cycle Costs could save up to 49 TWh and 20 MtCO 2-eq in 2020 and be economically beneficial to the European end-user. - Research highlights: → A methodology based on Life Cycle Analysis is applied to European air conditioners. → Environmental impacts are mainly due to energy consumption. → There is a high potential for energy savings at very low costs for end users.

75 FR 7987 - Energy Conservation Standards for Residential Clothes Dryers and Room Air Conditioners: Public...

Science.gov (United States)

2010-02-23

... Conservation Standards for Residential Clothes Dryers and Room Air Conditioners: Public Meeting and... conservation standards for residential clothes dryers and room air conditioners; the analytical framework..., Mailstop EE-2J, Public Meeting for Residential Clothes Dryers and Room Air Conditioners, EERE-2007-BT-STD...

75 FR 14368 - Energy Conservation Standards for Residential Central Air Conditioners and Heat Pumps: Public...

Science.gov (United States)

2010-03-25

... Conservation Standards for Residential Central Air Conditioners and Heat Pumps: Public Meeting and Availability... conservation standards for residential central air conditioners and heat pumps; the analytical framework..., Mailstop EE-2J, Public Meeting for Residential Central Air Conditioners and Heat Pumps, EERE-2008-BT- STD...

Low-Flow Liquid Desiccant Air Conditioning: General Guidance and Site Considerations

Energy Technology Data Exchange (ETDEWEB)

Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.

2014-09-01

Dehumidification or latent cooling in buildings is an area of growing interest that has been identified as needing more research and improved technologies for higher performance. Heating, ventilating, and air-conditioning (HVAC) systems typically expend excessive energy by using overcool-and-reheat strategies to dehumidify buildings. These systems first overcool ventilation air to remove moisture and then reheat the air to meet comfort requirements. Another common strategy incorporates solid desiccant rotors that remove moisture from the air more efficiently; however, these systems increase fan energy consumption because of the high airside pressure drop of solid desiccant rotors and can add heat of absorption to the ventilation air. Alternatively, liquid desiccant air-conditioning (LDAC) technology provides an innovative dehumidification solution that: (1) eliminates the need for overcooling and reheating from traditional cooling systems; and (2) avoids the increased fan energy and air heating from solid desiccant rotor systems.

Development of multiplexing network for air conditioner systems; Eakon yo LAN system no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, T; Nakazawa, Y; Nakase, M; Sato, Y [Nissan Motor Co. Ltd., Tokyo (Japan); Nomura, M; Okasato, Y; Sunaga, H [Calsonic Corp., Tokyo (Japan)

1997-10-01

Plural air flap actuators of the air conditioner system in a vehicle have been integrated into a single-type actuator using two newly developed technologies: super-low-cost multiplexing network technology and digital motor control technology with a 1-bit A/D converter. The number of harnesses and connectors and the handling load of the air conditioner control microcomputer are reduced, so that we succeeded in sharply reducing the cost of the air conditioner system. 9 figs., 2 tabs.

Development of a solar-powered residential air conditioner: System optimization preliminary specification

Science.gov (United States)

Rousseau, J.; Hwang, K. C.

1975-01-01

Investigations aimed at the optimization of a baseline Rankine cycle solar powered air conditioner and the development of a preliminary system specification were conducted. Efforts encompassed the following: (1) investigations of the use of recuperators/regenerators to enhance the performance of the baseline system, (2) development of an off-design computer program for system performance prediction, (3) optimization of the turbocompressor design to cover a broad range of conditions and permit operation at low heat source water temperatures, (4) generation of parametric data describing system performance (COP and capacity), (5) development and evaluation of candidate system augmentation concepts and selection of the optimum approach, (6) generation of auxiliary power requirement data, (7) development of a complete solar collector-thermal storage-air conditioner computer program, (8) evaluation of the baseline Rankine air conditioner over a five day period simulating the NASA solar house operation, and (9) evaluation of the air conditioner as a heat pump.

[Verification of bacteriological safety of PCM 40 air conditioner].

Science.gov (United States)

Dumas, J L; Ducel, G; Rouge, J C

1991-01-01

This study assessed the bacteriological safety of the bedside air conditioner PCM 40 (Howorth Airtech), used for prevention of intraoperative hypothermia, by blowing filtered warm air through a special mattress. The 3 microns bacterial filter of the device released 2,968 +/- 5,618 particles of diameter less than 3 microns per m3 of room air, containing 78,798 +/- 37,243 of such particles per m3. The amount of bacteries in the air pulsed from the mattress was 30 +/- 41 cfu/m3 vs 120 cfu/m3 in the ambient air and in the hot air supply tubing it reached 6 +/- 5 cfu/m3 vs 175 +/- 77 cfu/m3. It is concluded that bacteriological data do not contra-indicate the use of this air conditioner in the operating theater. The only limitations for use are the position (prone or lateral position) and type of surgery (neurosurgery).

Energy and economic analysis of a building air-conditioner with a phase change material (PCM)

International Nuclear Information System (INIS)

Chaiyat, Nattaporn

2015-01-01

Highlights: • Phase change material of Rubitherm20 was applied with the air-conditioner under the climate of Thailand. • PCM was used to reduce cooling load and electrical power of the air-conditioner. • Mathematical model of the packed ball bed of PCM was presented to predict the thermal performance. - Abstract: In this study, a concept of using phase change material (PCM) for improving cooling efficiency of an air-conditioner had been presented under Thailand climate. Rubitherm20 (RT-20) was selected to evaluate the thermal performance by reducing the air temperature entering the evaporating coil. The model of PCM celluloid balls had been performed with the air-conditioner. For the experiment, 2 TR of R-134a air-conditioner was chosen to test a pack bed of PCM balls with thickness 40 cm. The pressure drops of the air flowing through the bed were considered with and without a set of by-pass tubes along the height of the storage bed. The mathematical model of the air-conditioner with the PCM storage was developed and verified with the testing results. From the study results, it could be seen that pressure drops of the bed with and without bypass tubes were nearly the same results. Thus, PCM ball pack bed using RT-20 without bypass tubes was used to improve the cooling efficiency of the air-conditioner. The experimental result of the modified unit was compared and verified with the mathematical model, which agreed quite well with the simulation result. Finally, the model was used to analyze the economic result, which found that the electrical consumption of the modified air-conditioner could be decreased around 3.09 kW h/d. The saving cost from the PCM bed could be 9.10% of 170.03 USD/y and the payback period was around 4.15 y

Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

KAUST Repository

Bettahalli Narasimha, Murthy Srivatsa

2016-04-26

Dehumidification is responsible for a large part of the energy consumption in cooling systems in high humidity environments worldwide. Improving efficiency is therefore essential. Liquid desiccants offer a promising solution for dehumidification, as desired levels of humidity removal could be easily regulated. The use of membrane contactors in combination with liquid desiccant is attractive for dehumidification because they prevent direct contact between the humid air and the desiccant, removing both the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface can lower the expected desiccation rate per unit of desiccant surface area. In this context, hollow fiber membranes present an attractive option for membrane liquid desiccant contactors because of their high surface area per unit volume. We demonstrate in this work the performance of polyvinylidene fluoride (PVDF) based triple-bore hollow fiber membranes as liquid desiccant contactors, which are permeable to water vapor but impermeable to liquid water, for dehumidification of hot and humid air.

Net private benefits of purchasing eco-labeled air conditioners and subsidization policies in China

International Nuclear Information System (INIS)

Sun, Junxiu; Yin, Haitao; Wang, Feng

2014-01-01

Built on a data set of 527 air conditioner models collected from an online retailer, this study investigates whether the savings that consumers realize on their private electricity bills from purchasing energy-efficient appliances compensate for the additional cost of the appliances on the market, and if not, the size of the gap between the savings and the cost. Our findings show that, except for the most energy-efficient category, the cost savings from using energy-efficient air conditioners does compensate for their higher price. Therefore, any government subsidy should be reserved for the most efficient products. For less energy-efficient appliances, the best policy may be to provide more effective information instead of a subsidy because the subsidy might attract consumers away from more energy-efficient air conditioners and result in an unwanted effect. - Highlights: • This paper analyses the net private benefits of purchasing eco-labeled air conditioners in China. • There is no need to subsidize less energy-efficient air conditioners. • The most recently proposed policy development in China is a reform headed in the right direction

Regeneration characteristics of desiccant rotor with microwave and hot-air heating

International Nuclear Information System (INIS)

Kubota, Mitsuhiro; Hanada, Takuya; Yabe, Satoshi; Matsuda, Hitoki

2013-01-01

Microwave heating, because of its advantages of direct and rapid heating of materials, has the potential to be employed as a novel regeneration method of desiccant rotors in humidity conditioners. We proposed a combined regeneration process, which combines microwave heating and conventional hot-air heating. The system is expected to achieve high heating rate during an initial regeneration period by assisting water desorption using the additional energy of the microwave. In this study, the regeneration characteristics of a desiccant rotor were experimentally investigated under conditions of microwave heating, hot-air heating, and combined heating at various microwave powers and hot-air temperatures. The effectiveness of the combined regeneration was evaluated in terms of the regeneration ratio, the initial regeneration rate, the temperature distribution in the rotor, and finally in terms of the energy consumption. It was demonstrated that combined heating was effective at leveling non-uniform temperature distribution in the rotor. Combined heating achieved higher ratios and initial rates in regeneration compared to just microwave and hot-air heating. This result was obviously attributed to the additional input of microwave energy, resulting that average rotor temperature increased by microwave absorption of rotor. Moreover, it was also effective for enhancement of regeneration to level the temperature distribution in the rotor by combination of two heating methods with different heating mechanisms. Both the initial regeneration rate and the equilibrium regeneration ratio for combined heating were found to increase as the microwave power increased. A linear relationship was observed with respect to microwave power. From the viewpoint of energy consumption, it may be possible to apply combined and microwave heating to humidity control systems that switch between adsorption and regeneration in short cycle times, if the conversion and absorption efficiencies of the

A hybrid air conditioner driven by a hybrid solar collector

Science.gov (United States)

Al-Alili, Ali

The objective of this thesis is to search for an efficient way of utilizing solar energy in air conditioning applications. The current solar Air Conditioners (A/C)s suffer from low Coefficient of Performance (COP) and performance degradation in hot and humid climates. By investigating the possible ways of utilizing solar energy in air conditioning applications, the bottlenecks in these approaches were identified. That resulted in proposing a novel system whose subsystem synergy led to a COP higher than unity. The proposed system was found to maintain indoor comfort at a higher COP compared to the most common solar A/Cs, especially under very hot and humid climate conditions. The novelty of the proposed A/C is to use a concentrating photovoltaic/thermal collector, which outputs thermal and electrical energy simultaneously, to drive a hybrid A/C. The performance of the hybrid A/C, which consists of a desiccant wheel, an enthalpy wheel, and a vapor compression cycle (VCC), was investigated experimentally. This work also explored the use of a new type of desiccant material, which can be regenerated with a low temperature heat source. The experimental results showed that the hybrid A/C is more effective than the standalone VCC in maintaining the indoor conditions within the comfort zone. Using the experimental data, the COP of the hybrid A/C driven by a hybrid solar collector was found to be at least double that of the current solar A/Cs. The innovative integration of its subsystems allows each subsystem to do what it can do best. That leads to lower energy consumption which helps reduce the peak electrical loads on electric utilities and reduces the consumer operating cost since less energy is purchased during the on peak periods and less solar collector area is needed. In order for the proposed A/C to become a real alternative to conventional systems, its performance and total cost were optimized using the experimentally validated model. The results showed that for an

Pulmonary function tests in air conditioner users | Vidya ...

African Journals Online (AJOL)

Background: Modernization has been implicated in the pathogenesis of allergic airway diseases. House dust, mites, and indoor air pollutants have been reported to cause elevation of serum IgE levels and/or enhancement of eosinophil activity. A component of modern lifestyle is the intense use of air-conditioners (AC) that ...

Potential CO{sub 2} reduction by implementing energy efficiency standard for room air conditioner in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Mahlia, T.M.I.; Masjuki, H.H.; Choudhury, I.A.; Saidur, R. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2001-09-01

This study attempts to predict the environmental impact of implementing an energy efficiency standard for room air conditioners in Malaysia. The ownership of room air conditioners has increased tremendously in this country. At present, there are about 528,792 room air conditioners in Malaysian households. In the year 2020, it will be about 1,511,276. The potential carbon dioxide reduction is based on the predicted electricity savings from implementing a minimum energy efficiency standard for room air conditioners. The electricity savings are calculated based on the predicted electricity consumption by a single air conditioner in the Malaysian household. The replacement of less efficient units of this appliance is reflected in reduced electricity consumption and emissions from power plants. The energy efficiency provisions of this regulation and agreement provide targets to save money, energy and, most importantly, to protect the environment. (Author)

Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

Energy Technology Data Exchange (ETDEWEB)

Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.; Lowenstein, A.

2014-09-01

Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by first overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.

Energy reduction of building air-conditioner with phase change material in Thailand

Directory of Open Access Journals (Sweden)

Nattaporn Chaiyat

2014-11-01

Full Text Available In this study, a concept of using phase change material (PCM for improving cooling efficiency of an air-conditioner had been presented under Thai climate. Paraffin waxes melting point at around 20 °C was selected to evaluate the thermal performance by reducing the air temperature entering the evaporating coil. The model of PCM celluloid balls had been performed with the air-conditioner. Moreover, the mathematical model of the air-conditioner with the PCM storage was developed and verified with the testing results. From the study results, it could be seen that the simulated data agreed quite well with the experimental result at the discrepant around 2–4%. Finally, the model was used to analyze the economic result which was found that the electrical consumption of the modified air-conditioner could be decreased 3.09 kW h/d. The electrical power consumption of the modified unit was 36.27 kW h/d at the operating time 15 h/d compared with 39.36 kW h/d of the normal unit at the operating time 12 h/d. The saving cost of the PCM bed could be 9.10% or 170.03 USD and the payback period was 4.15 y.

Potential Evaluation of Solar Heat Assisted Desiccant Hybrid Air Conditioning System

Science.gov (United States)

Tran, Thien Nha; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

The solar thermal driven desiccant dehumidification-absorption cooling hybrid system has superior advantage in hot-humid climate regions. The reasonable air processing of desiccant hybrid air conditioning system and the utility of clean and free energy make the system environment friendly and energy efficient. The study investigates the performance of the desiccant dehumidification air conditioning systems with solar thermal assistant. The investigation is performed for three cases which are combinations of solar thermal and absorption cooling systems with different heat supply temperature levels. Two solar thermal systems are used in the study: the flat plate collector (FPC) and the vacuum tube with compound parabolic concentrator (CPC). The single-effect and high energy efficient double-, triple-effect LiBr-water absorption cooling cycles are considered for cooling systems. COP of desiccant hybrid air conditioning systems are determined. The evaluation of these systems is subsequently performed. The single effect absorption cooling cycle combined with the flat plate collector solar system is found to be the most energy efficient air conditioning system.

Field Study on Humidification Performance of a Desiccant Air-Conditioning System Combined with a Heat Pump

Directory of Open Access Journals (Sweden)

Koichi Kawamoto

2016-01-01

Full Text Available A desiccant air-conditioning system was developed as a latent-load-processing air conditioner in a dedicated outdoor air system during the summer. This study investigated the application of this air-conditioning system to humidification during the winter without using make-up water, thereby eliminating the cause of microbial contamination in air-conditioning systems. The experiments were conducted with a system used for summer applications to determine the feasibility of adsorbing vapor from outdoor air and supplying it to an indoor space. The humidification performance, energy efficiency, and operating conditions were examined. Although the conditions were subpar because the experiments were performed with an actual dedicated outdoor air system, the results showed that it is possible to supply air with a minimum humidity ratio of 5.8 g/kg dry air (DA when the humidity ratio of outdoor air ranges from 1.8 to 2.3 g/kg DA. The minimum humidification performance required for a dedicated outdoor air system was achieved by increasing the airflow rate of the moisture-adsorption side to 2–3 times that of the humidification side. In addition, air leaking from the moisture-adsorption side to the humidification side, improving the mechanical structure, such as by the insulation of the moisture-adsorption side, and an efficient operating method were examined for humidification during the winter.

Research on a compact adsorption room air conditioner

International Nuclear Information System (INIS)

Yang, G.Z.; Xia, Z.Z.; Wang, R.Z.; Keletigui, Daou; Wang, D.C.; Dong, Z.H.; Yang, X.

2006-01-01

A novel compact adsorption room air conditioner with a cooling capacity of 1 kW has been designed, and two prototypes have been built. A two bed, continuous adsorption refrigeration cycle with heat recovery and mass recovery is adopted. Micropore spherical silica gel and water are selected as the working pair. A gravity heat pipe with methanol as working medium is designed to output the cooling. Experimental investigations have indicated that under typical air conditioning conditions, for the first prototype, a cooling capacity of 687 W and a COP (coefficient of performance) of 0.307 can be obtained. However, for the improved one, a cooling capacity of 790 W and a COP of 0.446 can be reached. It is also proved that the operating temperatures have strong influences on the performance. The designed room air conditioner can be driven by a low grade heat source ( o C) and has small dimensions of 300 mm (depth), 500 mm (width) and 950 mm (height)

ENERGY STAR Certified Non-AHRI Central Air Conditioner Equipment and Air Source Heat Pump

Data.gov (United States)

U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 5.0 ENERGY STAR Program Requirements for Air Source Heat Pump and Central Air Conditioner...

Improvement of Cooling Performance of a Compact Thermoelectric Air Conditioner Using a Direct Evaporative Cooling System

Science.gov (United States)

Tipsaenporm, W.; Lertsatitthanakorn, C.; Bubphachot, B.; Rungsiyopas, M.; Soponronnarit, S.

2012-06-01

This paper presents the results of tests carried out to investigate the potential application of a direct evaporative cooling (DEC) system for improving the performance of a compact thermoelectric (TE) air conditioner. The compact TE air conditioner is composed of three TE modules. The cold and hot sides of the TE modules were fixed to rectangular fin heat sinks. The DEC system produced cooling air that was used to assist the release of heat from the heat sinks at the hot side of the TE modules. The results showed that the cooling air dry bulb temperature from the DEC system achieved drops of about 5.9°C in parallel with about a 33.4% rise in relative humidity. The cooling efficiency of the DEC system varies between 72.1% and 81.5%. It increases the cooling capacity of the compact TE air conditioner from 53.0 W to 74.5 W. The 21.5 W (40.6%) increase represents the difference between the compact air conditioner operating with ambient air flowing through the TE module's heat sinks, and the compact air conditioner operating with the cooler air from the DEC system flowing through the TE module's heat sinks. In both scenarios, electric current of 4.5 A was supplied to the TE modules. It also has been experimentally proven that the coefficient of performance (COP) of the compact TE air conditioner can be improved by up to 20.9% by incorporating the DEC system.

Isolation and Identification of Pathogenic Fungi from Air Conditioners in Tutorial Rooms of the Faculty of Medicine, Universitas Padjadjaran

Directory of Open Access Journals (Sweden)

Gowre Govindasamy

2014-02-01

Full Text Available Background: Awareness about health problems caused by air conditioner is very important. Thus, it is crucial to have knowledge about proper maintenance of air conditioner. At the Faculty of Medicine, Universitas Padjadjaran, air conditioners are used in every tutorial rooms. This study was performed to provide adequate information on the fungi, such as Aspergillus, Penicillium and Mucor, found in air conditioners. Methods: A descriptive laboratory study was used to identify the presence and the type of pathogenic fungi from air conditioners in tutorial rooms. Thirty-four samples were collected from the air outlet grille of the air conditioners and cultured on Sabouraud agar at 27°C for 2 weeks. Fungi presence were then identified microscopically Results: The results showed that the majority of air conditioners in tutorial rooms of the Faculty of Medicine, University Padjadjaran contained many types of fungus that grew in Sabouraud agar. From 34 samples, thirty two samples were positive and 2 samples were negative. Various fungus have been identified, those were Penicillium (37.5%, Aspergillus (25%, Mucor (2.5% and unidentified (35% Conclusions : The majority of air conditioners in tutorial rooms of the Faculty of Medicine, University Padjadjaran contained many types of opportunistic fungus. [AMJ.2014;1(1:21–4

DEMONSTRATION AND TESTING OF AN EER OPTIMIZER SYSTEM FOR DX AIR-CONDITIONERS

Science.gov (United States)

2017-10-07

Conditioner and Any Web Connected Device Such as a Tablet, Phone, Laptop, or Desktop Computer. ............. 28  Figure 15. A Summary Screen Showing...efficiency specifications published by the Consortium for Energy Efficiency (CEEE) for new unitary air conditioning and heat pump systems5 establish Energy...Figure 14. Connection Diagram Showing Data Path between the Air Conditioner and Any Web Connected Device Such as a Tablet, Phone, Laptop, or Desktop

Noninvasive evaluation of the chronic influence of local air velocity from an air conditioner using salivary cortisol and skin caspase-14 as biomarkers of psychosomatic and environmental stress.

Science.gov (United States)

Yamaguchi, M; Nishimiya, H

2012-01-01

To demonstrate the possibility of evaluating the chronic influence of local air velocity from an air conditioner using noninvasive biomarkers. Over a consecutive 5-day period, 16 healthy young male adults were exposed to air flow from a whole ceiling-type air conditioner (low local air velocity) and from a commercial concentrated exhaust air conditioner (high local air velocity). Salivary cortisol was used as an index of the psychological effects and caspase-14, collected from the stratum corneum, was used as a marker of environmental stress on the skin. Local air velocity generated from the whole ceiling-type air conditioner where the subject's head was positioned was one-seventh that of the exhaust air conditioner. After exposure to the exhaust air conditioner for 5 days, salivary cortisol decreased significantly from morning to evening and skin caspase-14 gradually increased during the day. A significant increase in hydration index from the morning to the evening was found with the whole ceiling-type air conditioner. The effects of chronic exposure to air movement generated by an air conditioner may be quantified by measurement of salivary cortisol and skin caspase-14.

Active Desiccant-Based Preconditioning Market Analysis and Product Development

Energy Technology Data Exchange (ETDEWEB)

Fischer, J.

2001-01-11

modeling initially presented in the Phase 1 report. This section also provides a revised payback analysis comparing the active desiccant systems selected with the other, more conventional approaches to specialized outdoor air handling units listed in the Phase 1 report. This report concludes with a look at the importance of analyzing active desiccant systems on the basis of ''latent air conditioning'' and not the more traditional ''total cooling capacity''. Since handling latent load will always be the primary reason for using an active desiccant system, it is concluded that the technology must be positioned as a ''latent air conditioner'' in the marketplace. In past analyses, active desiccant systems have been too often compared with conventional cooling systems based on total cooling output. The resulting $/ton ratios that have resulted almost always made the active approach appear as if a very significant first-cost premium were required.

Influence of environmental characteristics and climatic factors on mites in the dust of air-conditioner filters.

Science.gov (United States)

Wu, J; Liu, Z G; Ran, P X; Wang, B

2009-12-01

To investigate mites in the dust of air-conditioner filters (MACF) in China, a total of 652 dust samples were collected from six cities: Guangzhou (n = 129), Nanchang (n = 127), Shanghai (n = 113), Xian (n = 93), Beijing (n = 93), and Shenyang (n = 79). Tarsonemus granarius was the most dominant species (87.2%). Dermatophagoides pteronyssinus and Dermatophagoides farinae only represented 7.0 and 3.0% of total mites, respectively. With latitude increasing, both mite occurrence rate (P air-conditioner age, utilization time and power. Wall and window type air-conditioner had higher risk of finding MACF than the floor type air-conditioner. As far as the cleaning interval time of ACF was concerned, higher risk ratio and the highest density of MACF were found in the time stage of >3, air-conditioner filters are potential indoor threat to asthma and allergy sufferers. In this study, we find that the storage mite Tarsonemus granarius is the predominant species of mites in the dust of air-conditioner filters (MACF). Thus, the possible clinical importance of T. granarius should cause more our attentions in the future. The abundance and distribution of MACF are also found significantly varied in different climatic regions of China. When we try to assess the possible risk of MACF, more attentions should be focused on subtropical region than temperate region. The influence analysis of environmental characteristics on the prevalence of MACF will shed light on the establishment of mite control strategy and the design of mite defense air-conditioner.

Desiccant wheels for air humidification: An experimental and numerical analysis

International Nuclear Information System (INIS)

De Antonellis, Stefano; Intini, Manuel; Joppolo, Cesare Maria; Molinaroli, Luca; Romano, Francesco

2015-01-01

Highlights: • The use of desiccant wheel to humidify an air stream is investigated. • Air humidification is obtained by extracting water vapour from outdoor air. • Experimental tests in winter humidification conditions are performed. • The design of the proposed humidification system is numerically analyzed. • Effects of boundary conditions on humidification capacity are investigated. - Abstract: In this work the use of a desiccant wheel for air humidification is investigated through a numerical and experimental approach. In the proposed humidification system, water vapour is adsorbed from outdoor environment and it is released directly to the air stream supplied to the building. Such a system can be an interesting alternative to steam humidifiers in hospitals or, more generally, in applications where air contamination is a critical issue and therefore adiabatic humidifiers are not allowed. Performance of the proposed system is deeply investigated and optimal values of desiccant wheel configuration parameters are discussed. It is shown that in the investigated conditions, which are representative of Southern Europe winter climate, the system can properly match the latent load of the building. Finally, power consumption referred to the primary source of the proposed humidification system is compared to the one of steam humidifiers. The present analysis is carried out through experimental tests of a desiccant wheel in winter humidification conditions and through a phenomenological model of the device, based on heat and mass transfer equations.

10 CFR Appendix F to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Room Air Conditioners

Science.gov (United States)

2010-01-01

... of Room Air Conditioners F Appendix F to Subpart B of Part 430 Energy DEPARTMENT OF ENERGY ENERGY... Conditioners 1. Test method. The test method for testing room air conditioners shall consist of application of the methods and conditions in American National Standard (ANS) Z234.1-1972, “Room Air Conditioners...

16 CFR Appendix H to Part 305 - Cooling Performance and Cost for Central Air Conditioners

Science.gov (United States)

2010-01-01

... RULEâ) Pt. 305, App. H Appendix H to Part 305—Cooling Performance and Cost for Central Air Conditioners... Split System Units Central Air Conditioners (Cooling Only): All capacities 10.9 23.0 Heat Pumps (Cooling... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cooling Performance and Cost for Central Air...

Dynamic performance of self-operated three-way valve used in a hybrid air conditioner

International Nuclear Information System (INIS)

Zhang, Penglei; Zhou, Dehai; Shi, Wenxing; Li, Xianting; Wang, Baolong

2014-01-01

A hybrid air conditioner combining a thermosyphon cycle with a vapor compression refrigeration cycle has a large energy saving potential compared with a common air conditioner for spaces requiring year-round cooling. The performance of the switch between the vapor compression mode and the thermosyphon mode largely impacts the safety and reliability of hybrid air conditioners. Therefore, a self-operated three-way valve is proposed. A thermodynamic model and a kinetic model are developed in this paper to evaluate the dynamic performance of the switch valve. The effects of the spring force constant, compressor discharging volume, fit clearance and piston length on the dynamic performance of the switch valve are analyzed. In conclusion, the proposed self-operated three-way valve can realize the switch operation accurately. - Highlights: •A self-operated three-way valve is proposed for hybrid air conditioners. •The thermodynamic model and kinetic model of the self-operated three-way valve are developed. •The validity of models is verified by experiments. •Effects of four main design parameters on the operating performance of the valve are researched

Performance curves of room air conditioners for building energy simulation tools

International Nuclear Information System (INIS)

Meissner, José W.; Abadie, Marc O.; Moura, Luís M.; Mendonça, Kátia C.; Mendes, Nathan

2014-01-01

Highlights: • Experimental characteristic curves for two room air conditioners are presented. • These results can be implemented in building simulation codes. • The energy consumption under different conditions can numerically determine. • The labeled higher energy efficiency product not always provides the best result. - Abstract: In order to improve the modeling of air conditioners in building simulation tools, the characteristic curves for total cooling capacity, sensible cooling capacity and energy efficiency ratio of two room units were determined. They were obtained by means of standard capacity tests on climatic chambers in a set of environmental conditions described by external dry- and internal wet bulb temperatures. Afterward, the performance of these two units and that of four other units, with and without taking into to account the thermodynamic variations of the surrounding environments on it, were compared using a whole building simulation program for simulating a conditioned space. The comparative analysis showed that the air conditioner with the higher energy efficiency rating not always provides the lowest power consumption in real conditions of use

Effect of operating conditions on performance of silica gel-water air-fluidised desiccant cooler

Directory of Open Access Journals (Sweden)

Rogala Zbigniew

2017-01-01

Full Text Available Fluidised desiccant cooling is reported in the literature as an efficient way to provide cooling for air-conditioning purposes. The performance of this technology can be described by electric and thermal Coefficients of Performance (COP and Specific Cooling Power (SCP. In this paper comprehensive theoretical study was carried out in order to assess the effect of operating conditions such as: superficial air velocity, desiccant particle diameter, bed switching time and desiccant filling height on the performance of fluidised desiccant cooler (FDC. It was concluded that FDC should be filled with as small as possible desiccant particles featuring diameters and should not be operated with shorter switching times than optimum. Moreover in order to efficiently run such systems superficial air velocities during adsorption and desorption should be similar. At last substantial effect of desiccant filling height on performance of FDC was presented.

Performance test of a grid-tied PV system to power a split air conditioner system in Surabaya

Science.gov (United States)

Tarigan, E.

2017-11-01

Air conditioner for cooling air is one of the major needs for those who live in hot climate area such as Indonesia. This work presents the performance test of a grid-tied PV system to power air conditioner under a hot tropical climate in Surabaya, Indonesia. A 800 WP grid-tied photovoltaic (PV) system was used, and its performance was tested to power a 0.5 pk of split air conditioner system. It was found that about 3.5 kWh daily energy was consumed by the tested air conditioner system, and about 80% it could be supplied from the PV system. While the other 20% was supplied by the grid during periods of low solar irradiation, 440 Wh of energy was fed into the grid during operation out of office hours. By using the grid-tied PV system, the energy production by PV system did not need to match the consumption of the air conditioner. However, a larger capacity of PV system would mean that a higher percentage of the load would be covered by PV system.

Development of a solar-powered residential air conditioner

Science.gov (United States)

1975-01-01

The initial objective of the program was the optimization (in terms of cost and performance) of a Rankine cycle mechanical refrigeration system which utilizes thermal energy from a flat solar collector for air conditioning residential buildings. However, feasibility investigations of the adsorption process revealed that a dessicant-type air conditioner offers many significant advantages. As a result, limited efforts were expended toward the optimization of such a system.

[Air-conditioner disease. Results of an industrial medicine survey (author's transl)].

Science.gov (United States)

Molina, C; Aiache, J M; Bedu, M; Menaut, P; Wahl, D; Brestowski, J; Grall, Y

1982-07-03

The results of a survey conducted in a company employing 1850 persons working in air-conditioned premises are reported. One hundred and five persons were examined, including 790 who mostly complained of respiratory disorders and 20 controls. Regular check-ups during the last two years have failed to reveal any serious disease. The most frequent complaints were rhinitis and tracheitis, especially among female employees. No alveolitis was observed. The finding of Bacillus subtilis in samples of ambient air and air-conditioner filters in conjunction with the presence of precipitating antibodies against crude extracts from these samples, suggested that the respiratory disorders might have been due to this microorganism. A multifactorial analysis demonstrated a statistically significant correlation between clinical symptoms and immunological disorders. The air-conditioner disease, therefore, may present as a benign condition.

Technologies for high performance and energy saving in room air conditioners. Shoenegata kokoritsu eakon ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Kawai, N. (Toshiba Corp., Tokyo (Japan))

1994-05-31

An energy saving inverter type air-conditioner was introduced. It is important to increase the efficiency in the low capacity zone below the rated capacity to realize the energy saving. For the reduction of peak, improving the efficiency in the high capacity operation is also necessary. The power consumption in compressor and in inverter is about 90 % of the total power consumption in air-conditioner. The other 10 % are distributed to the fan motor and the control unit. For achieving the energy saving, the reduction of this 10 % part is also necessary because this 10 % part is constant regardless of the capacity of air-conditioner. The compressor motor was modified to the brushless DC motor with rotor position detecting device to improve the rotor structure and the position detection system. The heat exchanger was changed to a room heat exchanger with slit pattern. For the outdoor heat exchanger, the complex curvature blade fan was adopted. The control system of air-conditioner was changed. The PMV was previously learned and input in the microcomputer to calculate the data. Resultantly, the power consumption was reduced by about 20 % as compared with the conventional air-conditioner. 10 figs., 1 tab.

[Fungus microbiota in air conditioners in intensive care units in Teresina, Piauí].

Science.gov (United States)

Mobin, Mitra; do Amparo Salmito, Maria

2006-01-01

With the aim of identifying the fungus microbiota in air conditioners in intensive care units (ICUs) within public and private hospitals in Teresina, Piauí, solid material was collected from ten different ICUs. Thirty-three species of Moniliaceae and Dematiaceae were isolated, which was the first report of these in Piauí. High frequencies of Aspergillus niger Van Tieghem (60%), Aspergillus fumigatus Fres (50%), Trichoderma koningii Oudem (50%) and Aspergillus flavus Link: Fr. (40%) were recorded. The air conditioner cleanliness validity had expired in all the ICUs, and the quantity of colony-forming units exceeded the levels permitted by Law 176/00 from the Ministry of Health. It is important to provide individual protection equipment for professionals, adopt hospital infection control measures, raise the awareness of the presence of fungus infection, improve air circulation around the environment, periodically clean the air conditioners, and make health professionals alert to the importance of these fungi in the hospital environment.

Air conditioner with three stages of indirect regeneration

International Nuclear Information System (INIS)

Worthington, M.N.

1987-01-01

An air conditioner is described comprising: a cabinet defining an internal evaporation chamber and having an air inlet and an air outlet; a heat exchanger mounted in the cabinet and defining an air movement path between the air inlet and the air outlet; means for supplying air to be cooled to the air inlet of the cabinet of movement through the air movement path of the heat exchanger in a heat exchanger relationship; air diversion means for continuously diverting some of the air emerging from the air outlet of the cabinet; and means in the evaporation chamber of the cabinet for recirculating spraying water into the chiller tube of the heat exchanger for interacting with the diverted air moving therethrough to evaporatively cool the heat exchanger

16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

Science.gov (United States)

2010-01-01

... RULEâ) Pt. 305, App. I Appendix I to Part 305—Heating Performance and Cost for Central Air Conditioners... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Heating Performance and Cost for Central Air Conditioners I Appendix I to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC...

Design of Air Ventilation System for Cargo Hold Vessels Using Solar Desiccant

Directory of Open Access Journals (Sweden)

Alam Baheramsyah

2017-09-01

Full Text Available One of the facilities and infrastructure of the vessel is the ventilation system in the cargo hold to maintain the quality. One attempt to avoid high moisture ratios is to provide a dry air supply by using desiccants. The purpose of this thesis is to design the system of air ventilation with solar desiccant by analysis the calculation with decrease air humidity ratio after passing desiccant rotor as well as fulfillment needs of heater and cooling system using heat of exhaust gas and seawater as well as fulfillment of electricity need using solar energy. From the result of analysis obtain to provide air supply in the cargo hold of 437.5 m3 / hour, the specification of rotor desiccant has a diameter of 550 mm with thickness 200 mm to decrease ratio of outside air humidity equal to 83.1% become 46.5%. Dehumidification air temperature of 47.7oC will be lowered to 35oC by using the sea water cooling media. As for the reactivation air heater requirement of 24.292 kW would be to fulfilled by utilizing the exhaust power of 498.12 kW. And for the electric power needs of the syetm is 34,488 wp will be supplied from the total solar module is 33 units with 345 wp per-capacity.

Requirements of office air conditioners. Pt. 1

Energy Technology Data Exchange (ETDEWEB)

Radtke, W

1988-01-01

New building designs and experiences gained in the past are reponsible for the considerable changes the requirements of air conditioners have gone through in recent years. Details are given on an exemplary air conditioning system designed for the Colonia Insurances building complex located in the city of Cologne. The ventilation requirements and hygienic conditions set out for air conditioned rooms call for outside air supplies, the careful selection of air intakes, and the filtering of intake air. Details are given on the efficiency and limits of combined natural window ventilation/artificial ventilation systems, the influence of window types, and the influence of building structures. The pressure conditions to be expected for larger building complexes in the case of natural ventilation should be assessed with the help of models put to wind tunnel tests.

Experimental performance study of a proposed desiccant based air conditioning system.

Science.gov (United States)

Bassuoni, M M

2014-01-01

An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system.

Swozzle based burner tube premixer including inlet air conditioner for low emissions combustion

Science.gov (United States)

Tuthill, Richard Sterling; Bechtel, II, William Theodore; Benoit, Jeffrey Arthur; Black, Stephen Hugh; Bland, Robert James; DeLeonardo, Guy Wayne; Meyer, Stefan Martin; Taura, Joseph Charles; Battaglioli, John Luigi

2002-01-01

A burner for use in a combustion system of a heavy-duty industrial gas turbine includes a fuel/air premixer having an air inlet, a fuel inlet, and an annular mixing passage. The fuel/air premixer mixes fuel and air into a uniform mixture for injection into a combustor reaction zone. The burner also includes an inlet flow conditioner disposed at the air inlet of the fuel/air premixer for controlling a radial and circumferential distribution of incoming air. The pattern of perforations in the inlet flow conditioner is designed such that a uniform air flow distribution is produced at the swirler inlet annulus in both the radial and circumference directions. The premixer includes a swozzle assembly having a series of preferably air foil shaped turning vanes that impart swirl to the airflow entering via the inlet flow conditioner. Each air foil contains internal fuel flow passages that introduce natural gas fuel into the air stream via fuel metering holes that pass through the walls of the air foil shaped turning vanes. By injecting fuel in this manner, an aerodynamically clean flow field is maintained throughout the premixer. By injecting fuel via two separate passages, the fuel/air mixture strength distribution can be controlled in the radial direction to obtain optimum radial concentration profiles for control of emissions, lean blow outs, and combustion driven dynamic pressure activity as machine and combustor load are varied.

The role of technology, product lifetime, and energy efficiency in climate mitigation: A case study of air conditioners in Japan

International Nuclear Information System (INIS)

Nishijima, Daisuke

2017-01-01

This study analyzed the impact on the life-cycle CO_2 emissions derived from a specific durable good (i.e., household air conditioners in this study) of industrial technology changes, product lifetime changes, and energy efficiency improvements. I proposed a comprehensive structural decomposition analysis including two factors of average lifetime and energy efficiency trend of household air conditioners and applied the decomposition method to the Japanese environmental input-output tables of 1990, 1995, 2000, and 2005. The empirical results show that “Household air-conditioner sector” itself contributed to reducing life-cycle CO_2 emissions derived from household air conditioners, while other sectors such as “On-site power generation sector” and “Retail trade sector” contributed to increasing life-cycle CO_2 emissions derived from household air conditioners. I also conducted combined scenario analysis about reduction potential of product lifetime and energy efficiency of air conditioners and the results showed the reduction rate of energy efficiency necessary for maintain CO_2 emissions in 2005 at 1990 level on each average lifetime scenario. (e.g. if average lifetime of air conditioners is shortened by 1 year, energy efficiency of air conditioners have to be further improved by 20.6% from current level. - Highlights: • This study provides a decomposition framework for air conditioner’s CO_2 emissions. • Technology, product lifetime and energy efficiency are considered in the framework. • “Household air conditioner” sector contributed to reducing CO_2 emissions largely. • “On-site power generation” indirectly contributed to increasing CO_2 emissions. • I showed the improvement rates of energy efficiency to achieve a reduction target.

Statistical analysis of the count and profitability of air conditioners.

Science.gov (United States)

Rady, El Houssainy A; Mohamed, Salah M; Abd Elmegaly, Alaa A

2018-08-01

This article presents the statistical analysis of the number and profitability of air conditioners in an Egyptian company. Checking the same distribution for each categorical variable has been made using Kruskal-Wallis test.

Feasibility study of a green energy powered thermoelectric chip based air conditioner for electric vehicles

International Nuclear Information System (INIS)

Miranda, Á.G.; Chen, T.S.; Hong, C.W.

2013-01-01

Traditional compressed-refrigerant air conditioning systems consume substantial energy that may reduce the driving performance and cruising mileage of electric vehicles considerably. It is crucial to design a new climate control system, using a direct energy conversion principle, to further aid in the commercialization of modern electric vehicles. A solid state air conditioner model consisting on TECs (thermoelectric chips) as the load, DSSCs (dye sensitized solar cells) as the renewable energy source and high power LiBs (lithium-ion batteries) as an energy storage device are considered for a personal mobility vehicle. The power management between the main power net and the solid state air conditioner interface is designed with an outer proportional-integral controller and an inner passivity based current controller with a loss included model for perfect tracking. This model is intended to comprise thermal and electrical elements which can be tunable for performance benchmarking and optimization of a solid state air conditioning system. Dynamic performance simulations of the solid-state air conditioner are performed, alongside guidelines for feasibility. - Highlights: • Alternative model extraction for dye sensitized solar cells. • Improved and computationally fast model for the cabin air temperature dynamics. • Euler–Lagrange loss included modeling of a buck converter. • Loss-included passivity based inner loop current control. • The thermoelectric chip air conditioner is tested in simulated cooling/heating scenarios

Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

KAUST Repository

Bettahalli Narasimha, Murthy Srivatsa; Lefers, Ryan; Fedoroff, Nina V.; Leiknes, TorOve; Nunes, Suzana Pereira

2016-01-01

the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface

Study of noise in offices with window-type room air-conditioners

International Nuclear Information System (INIS)

Shaikh, G.H.; Hashmi, R.; Shareef, A.

2005-01-01

A Study of Noise has been carried out in 17 private offices, with window-type room air-conditioners, to assess noise levels in these offices. A-Weighted equivalent sound-pressure levels (dB(A) LAeq) and equivalent octave-band sound-pressure levels (dB Leq) were measured in each office, and Preferred Speech Interference Levels (PSIL) evaluated. The results show that the interior noise-levels in these offices vary from 59.6 to 72.2 dB(A) LAeq. which are very high and much above the interior noise limits, recommended for offices by some individual workers. Some ways and means to limit its emission of high level of noise from the air conditioners are also discussed. (author)

Design of direct solar PV driven air conditioner

KAUST Repository

Huang, Bin-Juine; Hou, Tung-Fu; Hsu, Po-Chien; Lin, Tse-Han; Chen, Yan-Tze; Chen, Chi-Wen; Li, Kang; Lee, K.Y.

2015-01-01

). The measured OPB is found to be greater than 0.98 at instantaneous solar irradiation IT > 600 W m-2 if rpL > 1.71 RF approaches 1.0 (the air conditioner is run in 100% with solar power) at daily-total solar radiation higher than 13 MJ m-2 day-1, if rpL > 3.

Performance study of desiccant coated heat exchanger air conditioning system in winter

International Nuclear Information System (INIS)

Ge, T.S.; Dai, Y.J.; Wang, R.Z.

2016-01-01

Highlights: • Performance of desiccant coated heat exchanger AC system is predicted. • Effects of main operation parameters and climatic conditions are discussed. • Regeneration temperature of 30 °C is recommended under simulation condition. • Higher ambient humidity ratio results in increased humidity ratio of supply air. • Temperature of ambient air has neglectable effect on supply air. - Abstract: Conventional air source heat pump system faces several challenges when adopted in winter season. Solid desiccant air conditioning system can provide humidification and heating power simultaneously and can be driven by low grade thermal energy; it provides a good alternative for air source heat pump systems. However, conventional solid desiccant air conditioning system adopts desiccant wheel with high cost as core component, which hinders the development of such system. Recently, desiccant coated heat exchanger (DCHE) with low initial cost and high efficiency was developed and this paper aims to investigate performance of DCHE air conditioning system adopted in Shanghai winter season. Performance of the system is predicted by a developed mathematical model where supply air states, mass of humidification and coefficient of performance (COP) are adopted as performance indices to evaluate the feasibility and energy utilization ratio of the system. Effects of regeneration water temperature on system performance are analyzed. It is found that under the simulation condition, relatively low regeneration temperature (such as 20 °C) cannot meet the designed standard and relatively high regeneration temperature (such as 40 °C) provides too much extra heating power, thus moderate regeneration temperature around 30 °C is recommended. Meanwhile, switch time is a crucial operation parameter for the system to obtain satisfied supply air, switch time from 40 s to 80 s and from 70 s to 240 s are recommended for transient and average supply air states, respectively. Both

Air conditioner operation behaviour based on students' skin temperature in a classroom.

Science.gov (United States)

Song, Gook-Sup; Lim, Jae-Han; Ahn, Tae-Kyung

2012-01-01

A total of 25 college students participated in a study to determine when they would use an air conditioner during a lecture in a university classroom. The ambient temperature and relative humidity were measured 75 cm above the floor every minute. Skin temperatures were measured every minute at seven points, according to the recommendation of Hardy and Dubois. The average clothing insulation value (CLO) of subjects was 0.53 ± 0.07 CLO. The mean air velocity in the classroom was 0.13 ± 0.028 m/s. When the subjects turned the air conditioner both on and off, the average ambient temperatures, relative humidity and mean skin temperatures were 27.4 and 23.7 °C (p = 0.000), 40.9 and 40.0% (p = 0.528) and 32.7 and 32.2 °C (p = 0.024), respectively. When the status of the air conditioner was changed, the differences of skin temperatures in core body parts (head, abdomen and thigh) were not statistically significant. However, in the extremities (mid-lower arm, hand, shin and instep), the differences were statistically significant. Subjects preferred a fluctuating environment to a constant temperature condition. We found that a changing environment does not affect classroom study. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Performance of desiccant air conditioning system with geothermal energy under different climatic conditions

International Nuclear Information System (INIS)

El-Agouz, S.A.; Kabeel, A.E.

2014-01-01

Highlights: • The performance of the hybrid air conditioning system is studied. • The influence of important operating parameters are estimated. • The ventilation, makeup and mix cycles are investigated at different climate. • The highest COP of the hybrid air conditioning system is 1.03. • The hybrid system provides a human thermal comfort at different climates. - Abstract: Energy saving still and continue a major seek in our life, due to the continuous increase in energy consumptions. So, a desiccant air conditioning system with geothermal energy is conducted in the current study. The thermal analysis of air conditioning system with its different components desiccant wheel, solar collector, heat exchanger, ground heat exchanger and water spray evaporative cooler is presented. Three different air conditioning cycles are simulated in the current study for different zones like: hot-dry zone, warm-dry zone, hot-humid zone and the warm-humid zone. The results show that the desiccant air conditioning system successfully provides a better thermal comfort condition in different climates. This hybrid system significantly decreases the supplied air temperature from 12.7 to 21.7 °C at different climate zones. When ω in , air and T Reg increasing, COP decreases and the ventilation cycle provides the better COP. The highest COP value of the desiccant air conditioning system is about 1.03 while the lowest value is about 0.15. The SHR of makeup cycle is higher than that ventilation cycle at warm and hot-humid zone and vice versa at warm and hot-dry zone. The highest SHR value of the desiccant air conditioning system is about 0.99 while the lowest value is about 0.2. The T sup,air , ω sup,air , COP and SHR isolines may easily be used for pre-evaluating of various cooling cycles in different climates. The hybrid system provides a human thermal comfort at different climates

Ventilation air conditioner for a reactor container

International Nuclear Information System (INIS)

Ikegame, Noboru; Nakagawa, Takeshi.

1980-01-01

Purpose: To suppress the variations in the internal pressure of a reactor container and smoothly ventilate the reactor container. Constitution: The air conditioner provides an air-flow-rate-control damper, a purge-air supply fan, and a filter device in the air-supply pipe of a reactor container. Furthermore, it provides a pressure difference detector at a part of the container. The air-flow-rate-control damper is connected electrically through a position-modulator-comparison amplifier to the pressure difference detector. When the filtration becomes insufficient by clogging of the filter device and the internal pressure increased abruptly in the container, the pressure-difference detector can detect it, and the damper is operated by a pressure regulator and the comparator so as to control the air flow to the container. Thus, the internal pressure variation is controlled so as to easily ventilate the container. (J.P.N.)

Electric efficiency in lighting system and air conditioners replacement and automation of air conditioners split type in public buildings; Eficiencia eletrica na substituicao do sistema de iluminacao e de condicionadores de ar e automacao do sistema de condicionadores de ar tipo split em predios publicos

Energy Technology Data Exchange (ETDEWEB)

Vasconcellos, Arnulfo Barroso de; Apolonio, Roberto; Silva, Luciana Oliveira da; Gomes, Fernanda Leles [Universidade Federal de Mato Grosso (UFMT), MT (Brazil); Malheiro, Teresa Irene Ribeiro de Carvalho [Instituto Federal de Educacao, Ciencia e Tecnologia de Mato Grosso (IFMT), MT (Brazil); Barros, Regiane Silva de [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

2010-07-01

The reduction in expenditure on electricity is a major benefit not only consumers but also to utilities. In this context, this article examines the process of replacing the system of internal lighting, window type air conditioners and automation of Split type air conditioners from buildings of public institutions of the state of Mato Grosso during 2009 year and verifies the reduction in annual consumption of electric power and demand active power. Thus, measurements and calculations performed are presented for the interior lighting systems and air conditioners of these buildings before and after implementation of the process of replacing the system of internal lighting and window type air conditioners and automation of Split type air conditioners. This work is the result of integration among the Dealer Network Energy Rede Cemat, the Federal University of Mato Grosso (UFMT) and the Administration of all public buildings, where the academy answered these real issues, solving the specific problem presented. (author)

The application of fuzzy control on energy saving for multi-unit room air-conditioners

International Nuclear Information System (INIS)

Chiou, C.B.; Chiou, C.H.; Chu, C.M.; Lin, S.L.

2009-01-01

Most research, on energy saving methods for air-conditioners have focused on large chillers as its subject. As most school offices, laboratories, and classrooms are equipped with unitary systems for air-conditioning, this paper discusses methods for energy savings with regard to unitary systems. This paper will put forward the fuzzy temperature control method for multi-unit air-conditioners to enhance energy efficiency. The results show that the use of fuzzy control is efficient for energy saving as well as causing temperature control be steadier, even if there is a change to the thermal loading, the fuzzy control system is able to control the air-conditioning in stable conditions

Air conditioner for radioactive material handling facility

International Nuclear Information System (INIS)

Tanaka, Takeaki.

1991-01-01

An air conditioner intakes open-air from an open-air intake port to remove sands and sea salt particles by air filters. Then, natural and artificial radioactive particles of less than 1 μm are removed by high performance particulate filters. After controlling the temperature by an air heater or an air cooler, air is sent to each of chambers in a facility under pressure elevation by a blower. In this case, glass fibers are used as the filter material for the high performance particulate filter, which has a performance of more than 99.97% for the particles of 0.3 μm grain size. Since this can sufficiently remove the natural radioactive materials intruded from the outside, a detection limit value in each of the chambers of the facility can be set 10 -13 to 10 -14 μci/cm 3 in respect of radiation control. Accordingly, radiation control can be conducted smoothly and appropriately. (I.N.)

Experimental Determination of Demand Response Control Models and Cost of Control for Ensembles of Window-Mount Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Geller, Drew Adam [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Backhaus, Scott N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-29

Control of consumer electrical devices for providing electrical grid services is expanding in both the scope and the diversity of loads that are engaged in control, but there are few experimentally-based models of these devices suitable for control designs and for assessing the cost of control. A laboratory-scale test system is developed to experimentally evaluate the use of a simple window-mount air conditioner for electrical grid regulation services. The experimental test bed is a single, isolated air conditioner embedded in a test system that both emulates the thermodynamics of an air conditioned room and also isolates the air conditioner from the real-world external environmental and human variables that perturb the careful measurements required to capture a model that fully characterizes both the control response functions and the cost of control. The control response functions and cost of control are measured using harmonic perturbation of the temperature set point and a test protocol that further isolates the air conditioner from low frequency environmental variability.

Refrigerant lines in split-type air conditioners

Energy Technology Data Exchange (ETDEWEB)

Rettenberger, P

1979-01-01

Condensator and evaporating units of split-type air conditioners are evaluated and filled with the refrigerant by the producer. The line systems are hermetically closed and prevent the loss of refrigerant and the penetration of moisture or dirt. The best installation method is the 'bendable lines'. They combine flexibility and easy installation with the advantages of the copper pipe. Several ducting systems and their connecting elements like couplings and valves are described, their installation is explained. These flexible systems are especially suitable for small air-condition plants of the split-type the evaporating unit of which is portable and can put where it is desired.

Combination of air-source heat pumps with liquid desiccant dehumidification of air

International Nuclear Information System (INIS)

Zhang Li; Hihara, Eiji; Saikawa, Michiyuki

2012-01-01

Highlights: ► We propose a frost-free air-source heat pump system with integrated desiccant. ► The system can provide heating load continuously and humidify room. ► The coefficient of performance of the system is 2.6 at T a = −7 °C and RH = 80%. ► The heating load of solution is 3–4 times larger than cooling load of solution. - Abstract: This paper proposes a frost-free air source heat pump system with integrated liquid desiccant dehumidification, in which frosting can be retarded by dehumidifying air before entering an outdoor heat exchanger. And the water removed from the air is used to humidify a room. Simulation is carried out at a dry-bulb temperature of −7 to 5.5 °C and a relative humidity of 80% depending on the frosting conditions. The results show that the coefficient of performance (COP) is in the range of 2.6–2.9, which is 30–40% higher than that of heat pump heating integrated with an electric heater humidifying system. And it is found that the optimum value of the concentration of lithium chloride aqueous solution is 37% for the frost-free operation mode. Experiments are conducted for liquid desiccant system under low air temperature and high relative humidity conditions. Experimental results show that the dew point of the dehumidified air is decreased by 8 °C and the humidity ratio of the humidified air is kept at 8.1 g kg −1 , which ensures the frost-free operation of the heat pump evaporator and the comfortable level of room humidity simultaneously. The heating load of solution is 3–4.5 times larger than cooling load of solution, which agrees with the assumption given at the part of the simulation. Furthermore, the deviations between the calculated COP LHRU and the experimental results are within 33%.

Dry air preservation and corrosion prevention using desiccant dehumidification

International Nuclear Information System (INIS)

Tykesson, M.; Ashworth, C.

1991-01-01

The preservation and longevity of power station plants is a significant problem, particularly in cold shut down situations for prolonged periods of time, and also in storage of parts prior to installation. Power station protection and equipment preservation using the desiccant method is not new. For many years dehumidification machinery has been employed as a barrier to moisture related degradation. The first rotary desiccant dehumidifiers were installed within the power plant industry in the mid 1960s. Many of these first installations remain in operation today. In order to understand the functioning of a desiccant unit as compared with other air handling systems, it is essential to understand the fundamentals of a psychrometric chart. This article will attempt to give the reader an understanding of the subject. (author)

Product lifetime, energy efficiency and climate change: A case study of air conditioners in Japan.

Science.gov (United States)

Nishijima, Daisuke

2016-10-01

This study proposed a modelling technique for estimating life-cycle CO2 emissions of durable goods by considering changes in product lifetime and energy efficiency. The stock and flow of durable goods was modelled by Weibull lifetime distributions and the trend in annual energy efficiency (i.e., annual electricity consumption) of an "average" durable good was formulated as a reverse logistic curve including a technologically critical value (i.e., limit energy efficiency) with respect to time. I found that when the average product lifetime is reduced, there is a trade-off between the reduction in emissions during product use (use phase), due to the additional purchases of new, more energy-efficient air conditioners, and the increase in emissions arising from the additional production of new air conditioners stimulated by the reduction of the average product lifetime. A scenario analysis focused on residential air conditioners in Japan during 1972-2013 showed that for a reduction of average lifetime of 1 year, if the air conditioner energy efficiency limit can be improved by 1.4% from the estimated current efficiency level, then CO2 emissions can be reduced by approximately the same amount as for an extension of average product lifetime of 1 year. Copyright © 2016 Elsevier Ltd. All rights reserved.

Consumer life-cycle cost impacts of energy-efficiency standards for residential-type central air conditioners and heat pumps

International Nuclear Information System (INIS)

Rosenquist, Gregory; Chan, Peter; Lekov, Alex; McMahon, James; Van Buskirk, Robert

2001-01-01

In support of the federal government's efforts to raise the minimum energy-efficiency standards for residential-type central air conditioners and heat pumps, a consumer life-cycle cost (LCC) analysis was conducted to demonstrate the economic impacts on individual consumers from revisions to the standards. LCC is the consumer's cost of purchasing and installing an air conditioner or heat pump and operating the unit over its lifetime. The LCC analysis is conducted on a nationally representative sample of air conditioner and heat pump consumers resulting in a distribution of LCC impacts showing the percentage of consumers that are either benefiting or being burdened by increased standards. Relative to the existing minimum efficiency standard of 10 SEER, the results show that a majority of split system air conditioner and heat pump consumers will either benefit or be insignificantly impacted by increased efficiency standards of up to 13 SEER

Consumer life-cycle cost impacts of energy-efficiency standards for residential-type central air conditioners and heat pumps

Energy Technology Data Exchange (ETDEWEB)

Rosenquist, Gregory; Chan, Peter; Lekov, Alex; McMahon, James; Van Buskirk, Robert

2001-10-10

In support of the federal government's efforts to raise the minimum energy-efficiency standards for residential-type central air conditioners and heat pumps, a consumer life-cycle cost (LCC) analysis was conducted to demonstrate the economic impacts on individual consumers from revisions to the standards. LCC is the consumer's cost of purchasing and installing an air conditioner or heat pump and operating the unit over its lifetime. The LCC analysis is conducted on a nationally representative sample of air conditioner and heat pump consumers resulting in a distribution of LCC impacts showing the percentage of consumers that are either benefiting or being burdened by increased standards. Relative to the existing minimum efficiency standard of 10 SEER, the results show that a majority of split system air conditioner and heat pump consumers will either benefit or be insignificantly impacted by increased efficiency standards of up to 13 SEER.

[A patient with acute hypersensitivity pneumonitis with a diagnosis of air-conditioner lung, who responded to therapy].

Science.gov (United States)

Ishikawa, Rie; Kamiya, Hiroyuki; Ikushima, Souichiro; Oristu, Masaru; Takemura, Tamiko

2010-02-01

The patient was a 48-year-old woman and current smoker. In May 2007, she moved to a new residence. In the middle of the following month, she developed acute respiratory distress and a fever (38 degrees C) after running her air conditioner continuously throughout the night. The chest X-ray film showed diffuse infiltrative shadows in the middle and lower lung fields. After hospital admission, her oxygenation improved without treatment and the infiltrates improved over the clinical course. As a consequence, we suspected hypersensitivity pneumonitis. The bronchoalveolar lavage showed predominant lymphocytes of 72.6%, with a low CD 4/8 ratio of 0.2. Transbronchial lung biopsy findings corresponded to acute hypersensitivity pneumonitis. The results of the environmental challenge test were positive only when her air conditioner was on, resulting, in a diagnosis of air-conditioner lung. Several microorganisms were detected in an environmental sample, but 20 kinds of serum precipitating antibodies were negative on a thorough screening, so no responsible antigen could be identified. The patient's symptoms did not recur after her air conditioner was replaced.

Energy performance and consumption for biogas heat pump air conditioner

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhenjun [Architectural Engineering College, Qingdao Agricultural University, 266109 (China); Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Tianjin University, Tianjin, 300072 (China); Wu, Huaizhi; Wu, Meiling [Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Tianjin University, Tianjin, 300072 (China)

2010-12-15

Biogas engine-driven heat pump air conditioner is a new-style system which includes biogas engine-driven heat pump, primary heat exchanger, second heat exchanger, sprayed room and fans, pumps, etc. In summertime, the air can be reheated by the waste heat water from the biogas engine in the system, while the air can be reheated and humidified by the waste heat water in winter. Reducing or displacing electrical heating requirements can achieve the great opportunity for significant energy savings. This paper, therefore, aims to improve the energy performance of the AC system by using the waste heat from the biogas engine. The mathematic model was used to research the BHPAC. Explicitly, we investigated the influence of various factors including the outdoor air temperature and humidity in summer and winter. Results show that the biogas engine-driven heat pump air conditioner can save more energy than the electrical power heat pump. In summer, the minimum for percentage of primary energy saving for BHPAC is over 25%. With the outdoor air dry-bulb temperature and the relative humidity rises, the saving energy percentage rises. In winter, the minimum for percentage of primary energy saving for BHPAC is 37%. The more the outdoor air relative humidity of the outdoor air decreases, the more the BHPAC saves energy. It is proved that the system which is a highly actively fully utilizing energy technology has good partial load characteristic and good effects of energy saving. (author)

Analysis for SEER of variable speed room air conditioner in China. Paper no. IGEC-1-104

International Nuclear Information System (INIS)

Yitai, M.; Shengchun, L.; Lirong, M.

2005-01-01

In this paper, the calculation method for seasonal energy efficiency ratio (SEER) given in Standard JRA4046-1999 is analyzed and further modified. Based on temperature zone map of U.S., Japan and China and detailed weather data of eight Chinese cities in last 30 years, regional seasonal energy efficiency ratio (RSEER) and energy saving percentage of variable speed room air conditioner are analyzed and compared with various geographical regions in China. It is concluded that RSEER presents the associated effect of season, climate and geography, and therefore should be taken as an evaluation standard for room air conditioner, especially variable speed room air conditioner. Experimental measurements are conducted in the analysis to investigate the effect of energy efficiency ratio (EER) on the improvement of energy saving percentage and SEER. (author)

Desiccant wheels as gas-phase absorption (GPA) air cleaners: evaluation by PTR-MS and sensory assessment

DEFF Research Database (Denmark)

Fang, Lei; Zhang, G.; Wisthaler, A.

2008-01-01

Two experiments were conducted to investigate the use of the co-sorption effect of a desiccant wheel for improving indoor air quality. One experiment was conducted in a climate chamber to investigate the co-sorption effect of a desiccant wheel on the chemical removal of indoor air pollutants......; another experiment was conducted in an office room to investigate the resulting effect on perceived air quality. A dehumidifier with a silica-gel desiccant wheel was installed in the ventilation system of the test chamber and office room to treat the recirculation airflow. Human subjects, flooring...

Study of an aqueous lithium chloride desiccant system Part II: Desiccant regeneration

Energy Technology Data Exchange (ETDEWEB)

Fumo, Nelson [Universidad Nacional Experimental del Tachira, San Cristobal (Venezuela); Goswami, Yogi [University of Florida, Gainesville (United States)

2000-07-01

Desiccant systems have been proposed as alternative to handle the latent load in vapor compression air conditioning for energy saving. The air dehumidification occurs because of the difference in vapor pressure which let the moisture diffuse from the air to the liquid desiccant. The diffused moisture cause a dilution of the desiccant which must be regenerated to return it to the original conditions. This paper presents the results from a study of the performance of a packed tower regenerator for an aqueous lithium chloride desiccant dehumidification system. The rate of water evaporation, as well as the effectiveness of the regeneration process were assessed under the effects of variables such as air and desiccant flow rates, air temperature and humidity, and desiccant temperature and concentration. A variation of the oeberg and Goswami mathematical model was used to predict the experimental findings given satisfactory results. [Spanish] Se han propuesto sistemas desecantes para hacerse cargo de la carga latente en acondicionamiento de aire por compresion de vapor para el ahorro de energia. La deshumidificacion del aire ocurre en razon de la diferencia de presion de vapor que deja la humedad difusa del aire en el desecante liquido. La humedad difusa del aire origina una dilucion del desecante el cual debe de ser regenerado para regresarlo a sus condiciones originales. Este documento presenta los resultados de un estudio sobre el comportamiento de un regenerador de torre empacada para un sistema de deshumidificacion de solucion desecante de cloruro de litio. El regimen de evaporacion de agua, asi como tambien la efectividad del proceso de regeneracion que se evaluo bajo los efectos de variables tales como los regimenes de flujo de aire y de desecante, temperatura del aire y humedad, y temperatura y concentracion del desecante. Una variacion del modelo matematico de Oberg y Goswami se uso para predecir los resultados experimentales que dieron resultados satisfactorios.

Thermodynamic analysis of an innovative liquid desiccant air conditioning system to supply potable water

International Nuclear Information System (INIS)

Ahmed, M.A.; Gandhidasan, P.; Zubair, Syed M.; Bahaidarah, Haitham M.

2017-01-01

Highlights: • The study objective is to reduce the energy consumption of desiccant AC system. • Heat and mass losses are recovered in the proposed system using a condenser. • The conventional and the proposed systems are compared in terms of COP. • The proposed system performance is better than the conventional system. • The proposed system produces freshwater in addition to space cooling. - Abstract: Liquid desiccant air conditioning systems are cost-effective, environmentally friendly and energy efficient techniques, especially in coastal areas. In the conventional liquid desiccant air conditioning system, the scavenging air is expelled into the atmosphere carrying a considerable amount of energy and water vapor. Thus, there is plenty of room to improve the system performance by recovering these losses. The proposed system consists of a conventional liquid desiccant air conditioning system plus a condenser. The aim of this study is to reduce the energy consumption by recovering the heat from the scavenging air using the condenser while also producing freshwater in addition to space cooling. Lithium chloride (LiCl) is used as the liquid desiccant for this study. The mathematical formulation for simultaneous heat and mass transfer between the condenser and the regenerator was developed to establish a comparison between the performance of the conventional and modified systems. Using the generated model, it is found that the modified system performance is 11.25% better than the conventional system and that it produces 86.4 kg of freshwater per hour as a by-product under the given conditions.

Domestic Refrigeration, Freezer, and Window Air Conditioner Service. Teacher Edition.

Science.gov (United States)

Clemons, Mark

This curriculum guide contains six units of instruction for a course in domestic refrigerator, freezer, and window air conditioner service. The units cover the following topics: (1) service fundamentals; (2) mechanical components and functions; (3) electrical components and control devices; (4) refrigerator and freezer service; (5) domestic ice…

Natural convection liquid desiccant loop as an auxiliary air conditioning system: investigating the operational parameters

Science.gov (United States)

Fazilati, Mohammad Ali; Alemrajabi, Ali Akbar; Sedaghat, Ahmad

2018-03-01

Liquid desiccant air conditioning system with natural convection was presented previously as a new generation of AC systems. The system consists of two three-fluid energy exchangers namely absorber and regenerator in which the action of air dehumidifying and desiccant regeneration is done, respectively. The influence of working parameters on system performance including the heat source and heat sink temperature, concentration of desiccant solution fills the system initially and humidity content of inlet air to regenerator is investigated experimentally. The heat source temperatures of 50 °C and 60 °C, heat sink temperatures of 15 °C and 20 °C and desiccant concentrations of 30% and 34%, are examined here. The inlet air to regenerator has temperature of 38.5 °C and three relative humidity of 14%, 38% and 44%. In all experiments, the inlet air to absorber has temperature of 31 °C and relative humidity of 75%. By inspecting evaluation indexes of system, it is revealed that higher startup desiccant concentration solution is more beneficial for all study cases. It is also observed although the highest/lowest temperature heat source/heat sink is most suitable for best system operation, increasing the heat source temperature should be accompanied with decreasing heat sink temperature. Using drier air stream for regenerator inlet does not necessarily improve system performance; and the air stream with proper value of humidity content should be employed. Finally after running the system in its best working condition, the coefficient of performance (COP) reached 4.66 which verified to be higher than when the same air conditioning task done by a conventional vapor compression system, in which case the COP was 3.38.

Experimental analysis and regression prediction of desiccant wheel behavior in high temperature heat pump and desiccant wheel air-conditioning system

DEFF Research Database (Denmark)

Sheng, Ying; Zhang, Yufeng; Sun, Yuexia

2014-01-01

The objectives of this study are to evaluate the performance of desiccant wheel (DW) in the running system and obtain the useful data for practical application. The combined influences of multiple variables on the performance of desiccant wheel are investigated based on evaluating the indexes...... of moisture removal capacity, dehumidification effectiveness, dehumidification coefficient of performance and sensible energy ratio. The results show that higher effect on the dehumidification is due to the regeneration temperature and outdoor air humidity ratio rather than the outdoor air temperature...... and the ratio between regeneration and process air flow rates. A simple method based on multiple linear regression theory for predicting the performance of the wheel has been proposed. The predicted values and the experimental data are compared and good agreements are obtained. Regression models are established...

Huffing air conditioner fluid: a cool way to die?

Science.gov (United States)

Phatak, Darshan R; Walterscheid, Jeffrey

2012-03-01

"Huffing," the form of substance abuse involving inhalants, is growing in popularity because of the ease and availability of chemical inhalants in many household products. The purpose in huffing is to achieve euphoria when the chemicals in question interact with the central nervous system in combination with oxygen displacement. The abuser is lulled into a false sense of safety despite the well-documented potential for lethal cardiac arrhythmia and the effects of chronic inhalant abuse, including multisystem organ failure, and brain damage. Huffing air conditioner fluid is a growing problem given the accessibility to outdoor units and their fluid components, such as difluorochloromethane(chlorodifluoromethane, Freon), and we have classified multiple cases of accidental death due to the toxicity of difluorochloromethane. Given the ubiquity of these devices and the vast lack of gating or security devices, they make an inviting target for inhalant abusers. Acute huffing fatalities have distinct findings that are present at the scene, given the position of the decedent and proximity to the air conditioner unit. The purpose of the autopsy in these cases is to exclude other potential causes of death and to procure specimens for toxicological analysis.

Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons.

Science.gov (United States)

Lv, Jinze; Zhu, Lizhong

2013-03-01

Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control, which significantly influences the transfer of pollutants between indoors and outdoors. To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants, a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants. During the period when the central ventilation system operated without air conditioning (AC-off period), concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels, due to the good linearity between indoor air and outdoor air (r(p) > 0.769, p air conditioner systems were working simultaneously (AC-on period), although the total levels of PAHs were increased, the concentrations and percentage of the particulate PAHs indoors declined significantly. The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.

Thermal analysis of a direct evaporative cooling system enhancement with desiccant dehumidification for vehicular air conditioning

International Nuclear Information System (INIS)

Alahmer, Ali

2016-01-01

Highlights: • Thermal analysis was conducted to design a desiccant evaporative cooling system for vehicular air conditioning. • EC is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter. • Drawbacks of evaporative cooler of increased weight and reduced COP. • A rotary desiccant dehumidifier with generation was combined with evaporative cooling to be more efficient. - Abstract: This manuscript analyzes the sub-systems of evaporative cooler (EC) combined with desiccant dehumidification and regeneration for automotive air conditioning purpose. The thermodynamic and psychometric analysis was conducted to design all evaporative cooling system components in terms of desiccant selection, regeneration process, compact heat exchanger and evaporative cooler. Moreover, the effect of the desiccant, heat exchanger and evaporative performances on the mass flow rate and water sprayed required for evaporative cooling system was investigated. The results show that the theoretical evaporative cooling design will achieve two main objectives: lower fuel consumption and less environmental pollutants. However, it has the two drawbacks in terms of increased weight and reduces the coefficient of performance (COP). The main remark is that evaporating cooling system is more efficient than the conventional air conditioning when the gasoline price is more than 0.34 $/liter.

Numerical Study of an Ejector as an Expansion Device in Split-type Air Conditioners for Energy Savings

Directory of Open Access Journals (Sweden)

Kasni Sumeru

2013-07-01

Full Text Available The present study describes a numerical approach for determining both the motive nozzle and constant-area diameters of an ejector as an expansion device, based on the cooling capacity of a split-type air-conditioner using R290 as refrigerant. Previous studies have shown that replacement of HCFC R22 with HC290 (propane in the air conditioner can improve the coefficient of performance (COP. The purpose of replacing the capillary tube with an ejector as an expansion device in a split-type air conditioner using HC290 is to further improve the COP. In developing the model, conservation laws of mass, momentum and energy equations were applied to each part of the ejector. The numerical results show that the motive nozzle diameter remains constant (1.03 mm under varying condenser temperatures, whereas the diameter of the constant-area decreases as the condenser temperature increases. It was also found that improvement of the COP can reach 32.90% at a condenser temperature of 55 °C. From the results mentioned above, it can be concluded that the use of an ejector can further improve the COP of a split-type air conditioner using HC290 as working fluid.

Influence of local air velocity from air conditioner evaluated by salivary and skin biomarkers

OpenAIRE

Yamaguchi, Masaki; Takahashi, Takayuki; Yoshino, Yuichiro; Sasaki, Makoto; Nishiyama, Hajime

2010-01-01

The purpose of this paper is to reveal both the psychosomatic and the physical effects of local air velocity from an air conditioner using biomarkers which can be collected noninvasively. Salivary α-amylase activity (SAA) and salivary cortisol were used as the indexes of psychosomatic effects. The total protein (TP) collected from stratum corneum was used as an index of the physical condition of dry skin. A continuous experiment over a 5 days period in summer was conducted using 8 healthy you...

Room air conditioner load control under summer comfort constraint

OpenAIRE

Da Silva , David; Brancaccio , M; Duplessis , Bruno; Adnot , J

2010-01-01

International audience; Load control options interest is growing because it can represent a response to future network investments and to congestion problems. In this frame, the present paper gives a methodology to quantify the value of load control for heat pumps (room air conditioners), in small tertiary and residential buildings, considering the occupant's comfort and the electrical grid needs for load shift. This methodology was applied to a small office building where simulations were ma...

Compressor motor for air conditioners realizing high efficiency and low cost; Kokoritsu tei cost wo jitsugenshita eakonyo asshukuki motor

Energy Technology Data Exchange (ETDEWEB)

Inaba, Y.; Kawamura, K.; Imazawa, K. [Toshiba Corp., Tokyo (Japan)

2000-01-01

The compressor motor accounts for most of the consumption of electric power in an air conditioner. To promote energy-saving, Toshiba has been progressively changing the compressor motors in its air conditioners to high-efficiency brushless DC motors. We have now developed a new compressor motor in order to achieve even greater energy-saving. A concentrated winding system was adopted featuring direct winding on the teeth of the stator core, for the first time in the industry. As a result, it was possible to realize a high-efficiency, compact, lightweight, and low-cost motor. Moreover, by constructing a new system for production, we were able to improve productivity and quality. The newly developed motor is expected to contribute to the further diffusion of energy-saving air conditioners. (author)

Small fan assisted air conditioner for thermal comfort and energy saving in Thailand

International Nuclear Information System (INIS)

Atthajariyakul, Surat; Lertsatittanakorn, Charoenporn

2008-01-01

From the fact that Thai people have a tolerance to high air temperature and are accustomed to high air movement from electric fans in non-air conditioned space, this paper proposes the use of small fan assisted air conditioners for human thermal comfort and energy saving in Thailand. In the study, a total 15 students were tested in a 2.5 x 3.5 x 2.5 m 3 test room equipped with a 12,000 Btu/h split type air conditioner. During the tests, the room air temperature was varied from 25, 26, 27 and 28 deg. C every 1 h. A small fan with 15 cm diameter was placed in front of each subject. In each hour, the small fan was varied to supply a small area with velocity from 0.2, 0.5, 1, 1.5 and 2 m/s. In each condition, the subjects were asked to vote for their thermal sensation. The results showed that the temperature set point could be increased up to 28 deg. C when a small fan was used to supply local air velocity from 0.5 to 2 m/s according to individual preference. This would reduce the electricity consumption of the air conditioning unit. According to the proposed method, this can save energy for office buildings in the commercial sector as high as 1959.51 GWh/year

Applying water cooled air conditioners in residential buildings in Hong Kong

International Nuclear Information System (INIS)

Chen Hua; Lee, W.L.; Yik, F.W.H.

2008-01-01

The objective of this study is to conduct a realistic prediction of the potential energy saving for using water cooled air conditioners in residential buildings in Hong Kong. A split type air conditioner with air cooled (AAC) and water cooled (WAC) options was set up for experimental study at different indoor and outdoor conditions. The cooling output, power consumption and coefficient of performance (COP) of the two options were measured and calculated for comparison. The experimental results showed that the COP of the WAC is, on average, 17.4% higher than that of the AAC. The results were used to validate the mathematical models formulated for predicting the performance of WACs and AACs at different operating conditions and load characteristics. While the development of the mathematical models for WACs was reported in an earlier paper, this paper focuses on the experimental works for the AAC. The mathematical models were further used to predict the potential energy saving for application of WACs in residential buildings in Hong Kong. The predictions were based on actual building developments and realistic operating characteristics. The overall energy savings were estimated to be around 8.7% of the total electricity consumption for residential buildings in Hong Kong. Wider use of WACs in subtropical cities is, therefore, recommended

Size optimization of stand-alone photovoltaic (PV) room air conditioners

International Nuclear Information System (INIS)

Chen, Chien-Wei; Zahedi, A.

2006-01-01

Sizing of a stand-alone PV system determines the main cost of the system. PV electricity cost is determined by the amount of solar energy received, hence the actual climate and weather conditions such as solar irradiance and ambient temperature affect the size required and cost of the system. Air conditioning demand also depends on the weather conditions. Therefore, sizing a PV powered air conditioner must consider the characteristics of local climate and temperature. In this paper, sizing procedures and special considerations for air conditioning under Melbourne's climatic conditions is presented. The reliability of various PV-battery size combinations is simulated by MATLAB. As a result, excellent system performance can be predicated.(Author)

Transient modeling of an air conditioner with a rapid cycling compressor and multi-indoor units

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei-Jiang [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Zhang, Chun-Lu [College of Mechanical Engineering, Tongji University, 4800 Cao An Highway, Shanghai 201804 (China)

2011-01-15

Rapid cycling the compressor is an alternative of the variable speed compressor to modulate the capacity of refrigeration systems for the purpose of energy saving at part-load conditions. The multi-evaporator air conditioner combined with the rapid cycling compressor brings difficulties in control design because of the sophisticated system physics and dynamics. In this paper the transient model of a multi-split air conditioner with a digital scroll compressor is developed for predicting the system transients under performance modulations. The predicted cycling dynamics are in good agreement with the experimental data. Based on the validated model, the impact of compressor idle power and cycle period to the part load performance is discussed. (author)

Transient modeling of an air conditioner with a rapid cycling compressor and multi-indoor units

Energy Technology Data Exchange (ETDEWEB)

Zhang Weijiang [Institute of Refrigeration and Cryogenics, Shanghai Jiaotong University, Shanghai 200240 (China); Zhang Chunlu, E-mail: chunlu.zhang@carrier.utc.co [College of Mechanical Engineering, Tongji University, 4800 Cao An Highway, Shanghai 201804 (China)

2011-01-15

Rapid cycling the compressor is an alternative of the variable speed compressor to modulate the capacity of refrigeration systems for the purpose of energy saving at part-load conditions. The multi-evaporator air conditioner combined with the rapid cycling compressor brings difficulties in control design because of the sophisticated system physics and dynamics. In this paper the transient model of a multi-split air conditioner with a digital scroll compressor is developed for predicting the system transients under performance modulations. The predicted cycling dynamics are in good agreement with the experimental data. Based on the validated model, the impact of compressor idle power and cycle period to the part load performance is discussed.

Transient modeling of an air conditioner with a rapid cycling compressor and multi-indoor units

International Nuclear Information System (INIS)

Zhang Weijiang; Zhang Chunlu

2011-01-01

Rapid cycling the compressor is an alternative of the variable speed compressor to modulate the capacity of refrigeration systems for the purpose of energy saving at part-load conditions. The multi-evaporator air conditioner combined with the rapid cycling compressor brings difficulties in control design because of the sophisticated system physics and dynamics. In this paper the transient model of a multi-split air conditioner with a digital scroll compressor is developed for predicting the system transients under performance modulations. The predicted cycling dynamics are in good agreement with the experimental data. Based on the validated model, the impact of compressor idle power and cycle period to the part load performance is discussed.

Theoretical modelling and experimental study of air thermal conditioning process of a heat pump assisted solid desiccant cooling system

DEFF Research Database (Denmark)

Nie, Jinzhe; Li, Zan; Hu, Wenju

2017-01-01

purification aimed at improving indoor air quality and reducing building energy consumption. The heat and moisture transfer in adsorption desiccant rotor was theoretical modelled with one-dimensional partial differential equations. The theoretical model was validated with experimental measurements...... system, the energy performance of HP-SDC was more efficient mainly due to high efficient air purification capacity, reduction of cooling load and raised evaporation temperature. The energy performance of HP-SDC was sensitive to outdoor humidity ratio. Further improvements of HP-SDC energy efficiency......Taking the integrated gaseous contaminants and moisture adsorption potential of desiccant material, a new heat pump assisted solid desiccant cooling system (HP-SDC) was proposed based on the combination of desiccant rotor with heat pump. The HP-SDC was designed for dehumidification, cooling and air...

Hardware-in-the-Loop Simulation of a Distribution System with Air Conditioners under Model Predictive Control: Preprint

Energy Technology Data Exchange (ETDEWEB)

Sparn, Bethany F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ruth, Mark F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Krishnamurthy, Dheepak [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pratt, Annabelle [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lunacek, Monte S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jones, Wesley B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wu, Hongyu [Kansas State University; Mittal, Saurabh [Mitre Corporation; Marks, Jesse [University of Missouri

2017-08-01

Many have proposed that responsive load provided by distributed energy resources (DERs) and demand response (DR) are an option to provide flexibility to the grid and especially to distribution feeders. However, because responsive load involves a complex interplay between tariffs and DER and DR technologies, it is challenging to test and evaluate options without negatively impacting customers. This paper describes a hardware-in-the-loop (HIL) simulation system that has been developed to reduce the cost of evaluating the impact of advanced controllers (e.g., model predictive controllers) and technologies (e.g., responsive appliances). The HIL simulation system combines large-scale software simulation with a small set of representative building equipment hardware. It is used to perform HIL simulation of a distribution feeder and the loads on it under various tariff structures. In the reported HIL simulation, loads include many simulated air conditioners and one physical air conditioner. Independent model predictive controllers manage operations of all air conditioners under a time-of-use tariff. Results from this HIL simulation and a discussion of future development work of the system are presented.

Energy and exergy performance analysis of a marine rotary desiccant air-conditioning system based on orthogonal experiment

International Nuclear Information System (INIS)

Zhu, Jun; Chen, Wu

2014-01-01

A novel marine rotary desiccant A/C (air-conditioning) system was developed and studied to improve energy utilization efficiency of ship A/C. The orthogonal experiment was first carried out to investigate the influence of various parameters of the marine rotary desiccant A/C system. During the orthogonal experiment the analysis of variance was used to exclude interference from the secondary influencing factor on system performance. The significant influencing factors of system were studied in great detail using the first and second laws of thermodynamics to find optimal setting parameters for best system performance. It is suggested from the analysis results that as regeneration temperature increases, the COP th (thermal coefficient of performance) and exergy efficiency of system (η e ) decreases by 46.9% and 38.8% respectively. They decrease in proportion to the increase of the temperature. η e reaches its maximum value of about 23.5% when the inlet humidity ratio of process air is 22 g/kg. Besides, the exergy loss of system concentrates on the regeneration air heater, the desiccant wheel and the regeneration air leaving the desiccant wheel, which account for 68.4%–81% of the total exergy loss. It can be concluded that applying the marine rotary desiccant A/C in high-temperature and high-humidity marine environment is advantageous. - Highlights: • Significant influencing factors of the system are found by the analysis of variance. • The change trends of the COP th and the η e are nearly proportional with the regeneration temperature. • The η e reaches its maximum value (about 23.5%) when the inlet humidity ratio of process air is 22 g/kg. • The contribution rate of the dry-bulb temperature of fresh air is up to 73.91% for the COP th . • Applying the marine rotary desiccant A/C in high-temperature and high-humidity marine environment is advantageous

Comparative analysis of objective techniques for criteria weighing in two MCDM methods on example of an air conditioner selection

Directory of Open Access Journals (Sweden)

Vujičić Momčilo D.

2017-01-01

Full Text Available This paper deals with comparative analysis of two different types of objective techniques for criteria weighing: Entropy and CRITIC and two MCDM methods: MOORA and SAW on example of an air conditioner selection. We used six variants for calculation of normalized performance ratings. Results showed that the decision of the best air conditioner was basically independent of the MCDM method used, despite the applied technique for determination of criteria weights. Complete ranking within all of the combinations of methods and techniques with diverse ratio calculation variants showed that the best ranked air conditioner was A7, while the worst ones were A5 and A9. Significant positive correlation was obtained for almost all the pairs of variants in all the combinations except for the MOORA - CRITIC combination with SAW - Entropy combination to have the highest correlations between variants (p < 0.01.

Simulated and experimental performance of split packaged air conditioner using refrigerant HC-290 as a substitute for HCFC-22

International Nuclear Information System (INIS)

Padalkar, Atul S.; Mali, Kundlik V.; Devotta, Sukumar

2014-01-01

This paper discusses the use of propane (HC-290) as a safe and energy efficient alternative to HCFC-22 in a typical split air conditioner with nominal cooling capacities up to 5.1 kW. Initially split air conditioner performance is simulated for cooling capacity, energy efficiency ratio (EER), and refrigerant charge. Tests were conducted for different test cases in a psychrometric test chamber with HCFC-22 and HC-290. The test conditions considered are as per Indian Standards, IS 1391 (1992) Part I. The various parameters considered were based on simulated performance with the objective to achieve maximum EER for the desired cooling capacity. As the flammability is an issue for HC-290, the reduction of HC-290 charge was another objective. Two different types of condensers, first with smaller size tubing and another parallel flow condenser (PFC) or minichannel condenser were used in order to reduce HC-290 charge. For HC-290, the highest EER achieved was 3.7 for cooling capacity 4.90 kW for a refrigerant charge of 360 g. The important safety aspects of using HC-290 in air conditioner are discussed. The refrigerant charge as per EN 378 for different cooling capacities and room sizes is also considered. -- Highlights: • Simulation for performance of split air conditioner has been done using HC-290 as a replacement to HCFC-22. • The safety aspects of HC-290 are discussed when used in split air conditioner. • HC-290 was tested in psychrometric test chamber as per IS 1391 part 1. • With PFC, HC-290 gave highest EER of 3.7 which was 37% higher than that of HCFC-22. • The lowest HC-290 charge used in test was 340 g which is well below LFL

LDDX: A High Efficiency Air Conditioner for DOD Buildings

Science.gov (United States)

2017-02-01

and the entire 2016 cooling season. The LDDX-WF prototype met its performance objectives to supply dry air and to modulate the Sensible Heat Ratio... heat transfer of the desiccant on the fin is an effective substitute for the conductive heat transfer of the aluminum fins used in a conventional...respectively. 22 The May 2014 laboratory operation of the LDDX-WF prototype was the first opportunity to measure heat and mass transfer

Towards a Residential Air-Conditioner Usage Model for Australia

Directory of Open Access Journals (Sweden)

Mark Goldsworthy

2017-08-01

Full Text Available Realistic models of occupant behaviour in relation to air-conditioner (a/c use are fundamentally important for developing accurate building energy simulation tools. In Australia and elsewhere, such simulation tools are inextricably bound both in legislation and in the design of new technology, electricity infrastructure and regulatory schemes. An increasing number of studies in the literature confirm just how important occupants are in determining overall energy consumption, but obtaining the data on which to build behaviour models is a non-trivial task. Here data is presented on air-conditioner usage derived from three different types of case study analyses. These are: (i use of aggregate energy consumption data coupled with weather, demographic and building statistics across Australia to estimate key predictors of energy use at the aggregate level; (ii use of survey data to determine characteristic a/c switch on/off behaviours and usage frequencies; and (iii use of detailed household level sub-circuit monitoring from 140 households to determine a/c switch on/off probabilities and their dependence on different building and occupant parameters. These case studies are used to assess the difficulties associated with translation of different forms of individual, aggregate and survey based information into a/c behaviour simulation models. Finally a method of linking the data gathering methodologies with the model development is suggested. This method would combine whole-of-house “smart”-meter data measurements with linked targeted occupant surveying.

Numerical Analysis and Geometry Optimisation of Vertical Vane of Room Air-conditioner

Directory of Open Access Journals (Sweden)

Al-Obaidi Abdulkareem Sh. Mahdi

2018-01-01

Full Text Available Vertical vanes of room air-conditioners are used to control and direct cold air. This paper aims to study vertical vane as one of the parameters that affect the efficiency of dissipating cold air to a given space. The vertical vane geometry is analysed and optimised for lower production cost using CFD. The optimised geometry of the vertical vane should have the same or increased efficiency of dissipating cold air and have lesser mass compared to the existing original design. The existing original design of vertical vane is simplified and analysed by using ANSYS Fluent. Efficiency of wind direction is define as how accurate the direction of airflow coming out from vertical vane. In order to calculate the efficiency of wind direction, 15° and 30° rotation of vertical vane inside room air-conditioner are simulated. The efficiency of wind direction for 15° rotation of vertical vane is 57.81% while efficiency of wind direction for 30° rotation of vertical vane is 47.54%. The results of the efficiency of wind direction are used as base reference for parametric study. The parameters investigated for optimisation of vertical vane are focused at length of long span, tip chord and short span. The design of 15% decreased in vane surface area at tip chord is the best optimised design of vertical vane because the efficiency of wind direction is the highest as 60.32%.

Acoustic resonance of outer-rotor brushless dc motor for air-conditioner fan

Science.gov (United States)

Lee, Hong-Joo; Chung, Shi-Uk; Hwang, Sang-Moon

2008-04-01

Generation of acoustic noise in electric motor is an interacting combination of mechanical and electromagnetic sources. In this paper, a brushless dc motor for air-conditioner fan is analyzed by finite element method to identify noise source, and the analysis results are verified by experiments, and sensitivity analysis is performed by design of experiments.

Experimental study on the performance of a multi-functional domestic air conditioner with integrated water heater

International Nuclear Information System (INIS)

Dong, Jiankai; Li, Hui; Yao, Yang; Jiang, Yiqiang; Zhang, Xinran

2017-01-01

Highlights: • A novel MDACWH was presented and experimentally studied. • MDACWH has high performance on making domestic hot water and air conditioning. • The time for heating water reduced to 22.0 min after modification. • Average COP reached 4.32, which was 1.58 times higher than the unmodified unit. - Abstract: The recovery of condenser heat is concerned one of the most effective methods to curb energy consumption in residential dwellings. Aiming at recovering the condenser heat of domestic air conditioner, this paper experimentally studied a multi-functional domestic air conditioner with integrated water heater (MDACWH) which can effectively provide space – cooling and domestic hot water simultaneously. The dynamic operation characteristics, such as hot water supply and energy efficiency were tested to verify the availability of the MDACWH. The results showed that the MDACWH can effectively heat the domestic hot water without losing its cooling capacity. It was also found that with the use of MDACWH, the coefficient of comprehensive energy performance of the MDACWH was about 1.58 times higher than that of the unmodified experimental unit. Furthermore, the water-heating time was shorten remarkably from 128.5 min to 22.0 min. The novel domestic air conditioner, compared with the unmodified initial prototype, can be more practical and provide significant energy savings in space-cooling and hot water supply.

Moving Advanced Desiccant Materials into Mainstream Non-CFC Cooling Products

Energy Technology Data Exchange (ETDEWEB)

Sand, J R [ORNL; Grossman, G [ORNL; Rice, C K [ORNL; Fairchild, P D [ORNL; Gross, I L [Engelhard/ICC

1994-01-01

Desiccant air-conditioning systems can be used as alternatives for conventional air-conditioning equipment in any commercial or residential building. Recent breakthroughs in desiccant materials technology and the creation of new markets by Indoor Air Quality issues make desiccant-based air-conditioning equipment practical for many space-conditioning applications.

Cardio-Muscular Conditioner

Science.gov (United States)

1993-01-01

In the mid-sixties, Gary Graham, a Boeing designer, developed a cardiovascular conditioner for a planned Air Force orbiting laboratory. After the project was cancelled, Graham participated in space station conditioning studies for the Skylab program. Twenty years later, he used this expertise to develop the Shuttle 2000-1, a physical therapy and athletic development conditioner, available through Contemporary Designs. The machine is used by football teams, sports clinics and medical rehabilitation centers. Cardiovascular fitness and muscular strength development are promoted through both kinetic and plyometric exercises.

Optimum dry-cooling sub-systems for a solar air conditioner

Science.gov (United States)

Chen, J. L. S.; Namkoong, D.

1978-01-01

Dry-cooling sub-systems for residential solar powered Rankine compression air conditioners were economically optimized and compared with the cost of a wet cooling tower. Results in terms of yearly incremental busbar cost due to the use of dry-cooling were presented for Philadelphia and Miami. With input data corresponding to local weather, energy rate and capital costs, condenser surface designs and performance, the computerized optimization program yields design specifications of the sub-system which has the lowest annual incremental cost.

Energy efficiency and energy saving air conditioners window and split type; Eficiencia energetica e economia de energia de condicionadores de ar tipo janela e split

Energy Technology Data Exchange (ETDEWEB)

Souza, Edson Palhares de; Cardoso, Rafael Balbino; Nogueira, Luiz Augusto Horta [Universidade Federal de Itajuba (EXCEN/UNIFEI), MG (Brazil). Centro de Excelencia em Eficiencia Energetica

2010-07-01

The air-conditioners of window end Split type are responsible for a significant portion of energy consumption in residential sector of Brazil, from 20% of the sector. This study evaluates the impact energy of the Seal Program PROCEL in air-conditioners of window end Split type, showing the efficiency gains for the country in terms of energy saving. For this evaluation it was considered the effects of temperature and loss of performance due to age, PROCEL Stamp Program resulted in a power savings of 664 GWh in air-conditioners of window type residential sector in 2008. (author)

Absorber and regenerator models for liquid desiccant air conditioning systems. Validation and comparison using experimental data

Energy Technology Data Exchange (ETDEWEB)

Krause, M.; Heinzen, R.; Jordan, U.; Vajen, K. [Kassel Univ., Inst. of Thermal Engineering, Kassel (Germany); Saman, W.; Halawa, E. [Sustainable Energy Centre, Univ. of South Australia, Mawson Lakes, Adelaide (Australia)

2008-07-01

Solar assisted air conditioning systems using liquid desiccants represent a promising option to decrease high summer energy demand caused by electrically driven vapor compression machines. The main components of liquid desiccant systems are absorbers for dehumidifying and cooling of supply air and regenerators for concentrating the desiccant. However, high efficient and validated reliable components are required and the design and operation have to be adjusted to each respective building design, location, and user demand. Simulation tools can help to optimize component and system design. The present paper presents new developed numerical models for absorbers and regenerators, as well as experimental data of a regenerator prototype. The models have been compared with a finite-difference method model as well as experimental data. The data are gained from the regenerator prototype presented and an absorber presented in the literature. (orig.)

Consumption-efficient regulation and switching concepts for air conditioners in buses; Verbrauchseffiziente Regelungs- und Verschaltungskonzepte fuer Omnibusklimaanlagen

Energy Technology Data Exchange (ETDEWEB)

Kaiser, Christian; Tegethoff, Wilhelm [TLK-Thermo GmbH, Braunschweig (Germany); Koehler, Juergen [TU Braunschweig (Germany). Inst. fuer Thermodynamik; Sonnekalb, Michael [Konvekta AG, Schwalmstadt (Germany)

2012-07-01

The reduction of the fuel consumption and the related reduction of CO{sub 2} emissions is one of the most important requirements in the current development of vehicles. This includes the development of fuel-efficient drive systems and the optimization of the so-called auxiliary users such as the air conditioner. The majority of the buses used today have an air conditioner in order to meet the increased demand of passengers for comfort. Since the operation of the air conditioner results in a significant increase in fuel consumption and thus in enhanced emissions of CO{sub 2}, an essential task of the development engineer is to minimize this additional consumption. In order to identify possible optimization potentials, a bus simulation model was developed which investigates not only exclusively compression refrigeration systems, but also is in communication with their relevant systems: heating circuit with engine cooling circuit, vehicle interior, on-board electrical system and vehicle longitudinal dynamics with the drive train. In the contribution under consideration, potentials of energy conservation should be identified that can be achieved due to the use of improved control and switching concepts. For this purpose, both the conventional R-744 (CO{sub 2}) bus air conditioning systems as well as alternative systems such as an ejector cycle were studied by means of a total vehicle simulation of the bus and compared.

Long-term indoor air conditioner filtration and cardiovascular health: A randomized crossover intervention study.

Science.gov (United States)

Chuang, Hsiao-Chi; Ho, Kin-Fai; Lin, Lian-Yu; Chang, Ta-Yuan; Hong, Gui-Bing; Ma, Chi-Ming; Liu, I-Jung; Chuang, Kai-Jen

2017-09-01

The association of short-term air pollution filtration with cardiovascular health has been documented. However, the effect of long-term indoor air conditioner filtration on the association between air pollution and cardiovascular health is still unclear. We recruited 200 homemakers from Taipei and randomly assigned 100 of them to air filtration or control intervention; six home visits were conducted per year from 2013 to 2014. The participants under air filtration intervention during 2013 were reassigned to control intervention in 2014. The air pollution measurements consisted of particulate matter less than or equal to 2.5μm in diameter (PM 2.5 ) and total volatile organic compounds (VOCs); blood pressure was monitored for each participant during each visit. The following morning, blood samples were collected after air pollution monitoring. The blood samples were used to analyze biological markers, including high sensitivity-C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG) and fibrinogen. Household information, including cleaning, cooking, and air conditioning, was collected by a questionnaire. Mixed-effects models were used to investigate the associations among air pollution measurements, blood pressure and biological markers. The results showed that increased levels of PM 2.5 and total VOCs were associated with increased hs-CRP, 8-OHdG and blood pressure. The health variables were higher among participants in the control intervention phase than among those in the air filtration intervention phase. We concluded that air pollution exposure was associated with systemic inflammation, oxidative stress and elevated blood pressure. The long-term filtration of air pollution with an air conditioner filter was associated with cardiovascular health of adults. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improvement of embryogenesis and regeneration by air desiccation in maize (zea mays l.)

International Nuclear Information System (INIS)

Morshed, S.; Siddique, B.; Islam, S.M.S.

2016-01-01

Calli derived from mature embryos of four maize varieties viz. Mohar, Khoi bhutta, Barnali and Shuvra were cultured in three basal media for regeneration (MS, N6 and 6N1) which individually supplemented with four hormonal combinations e.g. H1 = BAP 0.5 mg/l + IAA 0.0 mg/l, H2 = BAP 1.0 mg/l + IAA 0.5 mg/l, H3 = BAP 1.5 mg/l + IAA 1.0 mg/l and H4 = BAP 2.0 mg/l + IAA 1.5 mg/l. The highest frequency of regeneration was found with MS + H2 (41.35%) in Mohar, while the lowest was 17.37% in 6N1 + H1 for Barnali. To enhance the capability of regeneration, calli were pretreated by ten groups (6, 12, 18, 24, 30, 36, 42, 48, 54 and 60 h) of desiccation periods. The degrees of desiccation of pretreated calli were determined; and it was ranged as 6.23 to 40.52% where Khoi bhutta showed the maximum value at 60 h desiccation. The callus of Mohar exhibited the highest frequency of regeneration (75.24%) which desiccated for 48 h; and it was around 2 fold higher than the control. The variety Khoi bhutta showed the lowest efficiency (31.80%) when the callus was desiccated for 6 h. All the varieties performed their maximum regeneration at different periods, where 36, 30 and 42 h desiccation were optimal for Barnali (67.23%), Khoi bhutta (68.03%) and Shuvra (73.98%) accordingly. Analysis of variance (ANOVA) showed significant effect of maize genotype and periods of partial air desiccation to enhance regeneration at p<0.05 level. (author)

Desiccant-assisted cooling fundamentals and applications

CERN Document Server

Brum, Nisio

2014-01-01

The increasing concern with indoor air quality has led to air-quality standards with increased ventilation rates. Although increasing the volume flow rate of outside air is advisable from the perspective of air-quality, it is detrimental to energy consumption, since the outside air has to be brought to the comfort condition before it is insufflated to the  conditioned ambient. Moreover, the humidity load carried within outside air has challenging HVAC engineers to design cooling units which are able to satisfactorily handle both sensible and latent contributions to the thermal load. This constitutes a favorable scenario for the use of solid desiccants to assist the cooling units. In fact, desiccant wheels have been increasingly applied by HVAC designers, allowing distinct processes for the air cooling and dehumidification. In fact, the ability of solid desiccants in moisture removal is effective enough to allow the use of evaporative coolers, in opposition to the traditional vapor-compression cycle, resultin...

Deaths Due to Accidental Air Conditioner Compressor Explosion: A Case Series.

Science.gov (United States)

Behera, Chittaranjan; Bodwal, Jatin; Sikary, Asit K; Chauhan, Mohit Singh; Bijarnia, Manjul

2017-01-01

In an air-conditioning system, the compressor is a large electric pump that pressurizes the refrigerant gas as part of the process of turning it back into a liquid. The explosion of an air conditioner (AC) compressor is an uncommon event, and immediate death resulted from the blast effect is not reported in forensic literature. We report three such cases in which young AC mechanics were killed on the spot due to compressor blast, while repairing the domestic split AC unit. The autopsy findings, the circumstances leading to the explosion of the compressor, are discussed in this study. © 2016 American Academy of Forensic Sciences.

Performance Analysis of a Solar Dryer Equipped with a Recycling Air System and Desiccant Chamber

Directory of Open Access Journals (Sweden)

M.H Aghkhani

2013-09-01

Full Text Available Drying is a high energy consuming process. Solar drying is one of the most popular methods for dehydration of agricultural products. In the present study, the performance of a forced convection solar dryer equipped with recycling air system and desiccant chamber was investigated. The solar dryer is comprised of solar collector, drying chamber, silica jell desiccant chamber, air ducts, fan and measuring and controlling system. Drying rate and energy consumption in three levels of air temperature (40, 45 and 50 oC and two modes of drying (with recycling air and no-recycling with open duct system were measured and compared. The results showed that increasing the drying air temperature decreased the drying time and increased the energy consumption in the mode of non-recycling air system. The dryer efficiency and drying rate were better in the mode of recycling air system than open duct system. The highest dryer efficiency was obtained from drying air temperature of 50 oC and the mode of recycling air system. In general, the efficiency of solar collector and the highest efficiency of the dryer were 0.34 and 0.41, respectively.

Development of a solar-powered residential air conditioner: Economic analysis

Science.gov (United States)

1975-01-01

The results of investigations aimed at the development of cost models to be used in the economic assessment of Rankine-powered air conditioning systems for residential application are summarized. The rationale used in the development of the cost model was to: (1) collect cost data on complete systems and on the major equipment used in these systems; (2) reduce these data and establish relationships between cost and other engineering parameters such as weight, size, power level, etc; and (3) derive simple correlations from which cost-to-the-user can be calculated from performance requirements. The equipment considered in the survey included heat exchangers, fans, motors, and turbocompressors. This kind of hardware represents more than 2/3 of the total cost of conventional air conditioners.

Experimental performance of a liquid desiccant dehumidification system under tropical climates

International Nuclear Information System (INIS)

Jain, Sanjeev; Tripathi, Sagun; Das, Rajat Subhra

2011-01-01

Research highlights: → Indirect contact between air and desiccant using a porous surface to avoid carryover. → Humidity effectiveness and moisture removal rate reported under varying conditions. → Humidity effectiveness with LiCl as desiccant in the range 0.36-0.45. → Mass transfer characteristic of contactor surface restricted system performance. -- Abstract: The current energy crisis, climate change and increased air conditioning demands have generated a need for developing technologies based on renewable energy sources. Foremost amongst the cooling technologies are the sorption technologies working on low grade heat that can be supplied by solar energy. Liquid desiccant technologies seem to be a promising option as these tend to have higher thermal COPs, lower regeneration temperatures, facilitate simultaneous cooling and ease of storage of concentrated desiccant that can be used during the nonsunshine hours. But few concerns like carryover of liquid desiccant in air require further investigations. The liquid desiccant system under study incorporates a double channelled exchanger for air to liquid desiccant heat and mass transfer. It provides a large surface area for air/desiccant contact and reduces the carryover as direct contact between desiccant and air is minimized unlike spray towers, packed bed and falling film designs. Desiccant is heated in a plate heat exchanger using hot water and then regenerated in a regenerator. The set-up comprises of a dehumidifier, along with a regenerator, a cooling tower, plate heat exchangers and a control unit. Experiments were conducted on the system using calcium chloride and lithium chloride as desiccants by varying parameters like inlet air conditions, hot water temperature and desiccant concentration in order to evaluate the performance of the system under different operating conditions. The performance of the system is presented in terms of moisture removal rates, dehumidifier and regenerator effectiveness.

ENERGY STAR Certified Non-AHRI Central Air Conditioner Equipment and Air Source Heat Pump

Science.gov (United States)

Certified models meet all ENERGY STAR requirements as listed in the Version 5.0 ENERGY STAR Program Requirements for Air Source Heat Pump and Central Air Conditioner Equipment that are effective as of September 15, 2015. A detailed listing of key efficiency criteria are available at http://www.energystar.gov/index.cfm?c=airsrc_heat.pr_crit_as_heat_pumps Listed products have been submitted to EPA by ENERGY STAR partners that do not participate in the AHRI certification program. EPA will continue to update this list with products that are certified by EPA-recognized certification bodies other than AHRI. The majority of ENERGY STAR products, certified by AHRI, can be found on the CEE/AHRI Verified Directory at http://www.ceedirectory.org/

Experimental study on split air conditioner with new hybrid equipment of energy storage and water heater all year round

International Nuclear Information System (INIS)

Wang Shaowei; Liu Zhenyan; Li Yuan; Zhao Keke; Wang Zhigang

2005-01-01

This paper presents a split air conditioner with a new hybrid equipment of energy storage and water heater all year round (ACWES). The authors made a special design on the storage tank to adjust the refrigerant capacity in the storage coils under different functions, instead of adding an accumulator to the system. An ACWES prototype, rebuilt from an original split air conditioner, has been finished, and experimental study of the operation processes of the prototype was done from which some important conclusions and suggestions have been made, which were helpful in the primary design and improvement of an ACWES system for potential users

Performance evaluation of a stack cooling system using CO{sub 2} air conditioner in fuel cell vehicles

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Chul; Won, Jong Phil [Thermal Management Research Center, Korea Automotive Technology Institute, Chungnam 330-912 (Korea); Park, Yong Sun; Lim, Tae Won [Corporate Research and Development Division, Hyundai-Kia Motors, Gyeonggi 449-912 (Korea); Kim, Min Soo [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744 (Korea)

2009-01-15

A relation between the heat release from a fuel cell stack and an air conditioning system's performance was investigated. The air conditioning system installed in a fuel cell vehicle can be used for stack cooling when additional stack heat release is required over a fixed radiator capacity during high vehicle power generation. This study investigated the performance of a stack cooling system using CO{sub 2} air conditioner at various operating conditions. Also, the heat releasing effectiveness and mutual interference were analyzed and compared with those for the conventional radiator cooling system with/without cabin cooling. When the radiator coolant inlet temperature and flow rate were 65 C and 80 L/min, respectively, for the outdoor air inlet speed of 5 m/s, the heat release of the stack cooling system with the aid of CO{sub 2} air conditioner increased up to 36% more than that of the conventional radiator cooling system with cabin cooling. Furthermore, this increased by 7% versus the case without cabin cooling. (author)

Pulmonary functions in air conditioner users.

Science.gov (United States)

Khaliq, Farah; Sharma, Sameer; Tandon, O P

2006-01-01

Air conditioning may affect human health since it has profound effect on our environment, than just lowering temperature. The present study was planned to assess the effect of air conditioners (AC) on pulmonary functions in young healthy non-smoker males. The study group comprised of ten subjects who were using AC's in their cars for at least 1 hr daily since last 6 months. While ten subjects who did not use AC at all served as controls. The pulmonary functions were assessed using PK Morgan 232 spirometer in a closed room. The peak expiratory flow rate (PEFR) and Forced expiratory flow between 25-75% of vital capacity (FEF25-75) were significantly reduced in subjects using car AC's. Inspiratory flow rates also showed a trend towards decline in AC users but could not reach the level of significance. The lung volumes and capacities were not significantly different in the two groups except for forced expiratory volume in 0.5 sec (FEV 0.5 sec), which also decreased in AC users. The airway resistance and lung compliance did not show significant change. In the presence of normal FEV1, reduced FEF25-75% which is the flow rate over the middle half of vital capacity, is an evidence of mild airflow limitation. The result is suggestive of predisposition of AC users towards respiratory disorders in form of mild airflow restriction.

Simulation and parameter analysis of a two-stage desiccant cooing/heating system driven by solar air collectors

International Nuclear Information System (INIS)

Li, H.; Dai, Y.J.; Köhler, M.; Wang, R.Z.

2013-01-01

Highlights: ► A solar desiccant cooling/heating system is simulation studied. ► The mean deviation is about 10.5% for temperature and 9.6% for humidity ratio. ► The 51.7% of humidity load and 76% of the total cooling can be handled. ► About 49.0% of heating load can be handled by solar energy. ► An optimization of solar air collector has been investigated. - Abstract: To increase the fraction of solar energy might be used in supplying energy for the operation of a building, a solar desiccant cooling and heating system was modeled in Simulink. First, base case performance models were programmed according to the configuration of the installed solar desiccant system and verified by the experimental data. Then, the year-round performance about the system was simulated. Last, design parameters of solar air collectors were optimized that include collector area, air leakage and thermal insulation. Comparison between numerical and experimental results shows good agreement. During the simulation, the humidity load for 63 days (51.7%) can be totally handled by the two-stage desiccant cooling unit. For seasonal total heating load, about 49.0% can be handled by solar energy. Based on optimized results, the thermal energy subsystem functioned to its expected performance in solar energy collection and thermal storage

Life cycle analysis of retrofitting with high energy efficiency air-conditioner and fluorescent lamp in existing buildings

International Nuclear Information System (INIS)

Techato, Kua-anan; Watts, Daniel J.; Chaiprapat, Sumate

2009-01-01

Life cycle analysis of mercury in discarded low energy efficiency fluorescent lamps (36 W) and of HCFC in air-conditioners (12,000 Btu) removed from service has been conducted in this study. The objective was to find out the environmental impact (EDIP 1997 category, waste evaluation) of the products that appear in the waste stream as a result of facility upgrades. The scope of the study starts from retrofitting of the lamps and air-conditioners through recycling and disposal. For a 36 W fluorescent lamp, the bulk waste 1.64E-5 kg, hazardous waste 1.11E-4 kg, radioactive waste 1.09E-9 kg, and slag-ash 6.02E-7 kg occurred at the end of life of the retrofitting cycle. For a 12,000 Btu air-conditioner, the bulk waste 0.58 kg, hazardous waste 0.11 kg, radioactive waste 0.0002 kg, and slag-ash 0.01 kg also occurred at the end of life of the retrofitting cycle. These small amounts become important when viewed at the country level. These quantities imply that the policy makers who deal with hazardous waste should be aware of this waste-generating characteristic before issuing any pertinent policy. Consideration of this characteristic and planning for appropriate waste management methods at the beginning stage will reduce any future problem of contamination by the hazardous waste

Life cycle analysis of retrofitting with high energy efficiency air-conditioner and fluorescent lamp in existing buildings

Energy Technology Data Exchange (ETDEWEB)

Techato, Kua-anan [International Postgraduate Programs in Environmental Management (Hazardous Waste Management) and ERI (Energy Research Institute), Chulalongkorn University, Bangkok 10330 (Thailand); Watts, Daniel J. [Otto H. York Center for Environmental Engineering and Science, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Chaiprapat, Sumate [Department of Civil Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai Campus, Hat Yai, Songkhla 90112 (Thailand); National Center of Excellence for Environmental and Hazardous Waste Management-Satellite Center at Prince of Songkla University (Thailand)

2009-01-15

Life cycle analysis of mercury in discarded low energy efficiency fluorescent lamps (36 W) and of HCFC in air-conditioners (12,000 Btu) removed from service has been conducted in this study. The objective was to find out the environmental impact (EDIP 1997 category, waste evaluation) of the products that appear in the waste stream as a result of facility upgrades. The scope of the study starts from retrofitting of the lamps and air-conditioners through recycling and disposal. For a 36 W fluorescent lamp, the bulk waste 1.64E-5 kg, hazardous waste 1.11E-4 kg, radioactive waste 1.09E-9 kg, and slag-ash 6.02E-7 kg occurred at the end of life of the retrofitting cycle. For a 12,000 Btu air-conditioner, the bulk waste 0.58 kg, hazardous waste 0.11 kg, radioactive waste 0.0002 kg, and slag-ash 0.01 kg also occurred at the end of life of the retrofitting cycle. These small amounts become important when viewed at the country level. These quantities imply that the policy makers who deal with hazardous waste should be aware of this waste-generating characteristic before issuing any pertinent policy. Consideration of this characteristic and planning for appropriate waste management methods at the beginning stage will reduce any future problem of contamination by the hazardous waste. (author)

Utilization of air conditioner condenser as water heater in an effort to energy conservation

Science.gov (United States)

Sonawan, Hery; Saputro, Panji; Kurniawan, Iden Muhtar

2018-04-01

This paper presents an experimental study of utilization of air conditioner condenser as water heater. Modification of existing air conditioner system is an effort to harvest waste heat energy from condenser. Modification is conducted in order to test the system into two mode tests, first mode with one condenser and second mode with two condensers. Harvesting the waste heat from condenser needs a theoretical and practice study to see how much the AC performance changes if modifications are made. It should also be considered how the technique of harvesting waste heat for water heating purposes. From the problem, this paper presents a comparison between AC performance before and after modification. From the experiment, an increase in compressor power consumption is 4.3% after adding a new condenser. The hot water temperature is attained to 69 °C and ready for warm bath. The increase in power consumption is not too significant compared to the attainable hot water temperature. Also seen that the value of condenser Performance Factor increase from 5.8 to 6.25 or by 7.8%.

Orbiting compressor for residential air-conditioners

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Jin; Kim, Woo Young; Ahn, Jong Min [Department of Mechanical Engineering, University of Incheon, 12-1 Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea)

2010-01-15

A new type of compressor, called an orbiting compressor, is introduced in this paper. The orbiting compressor is characterized by an orbiting piston, and the piston or orbiter consists of a circular base plate and a ring type vane protruding vertically from the base plate. The orbiter is made to orbit in an annular space formed between two concentric circular walls via an Oldham-ring mechanism, producing two sealed gas pockets on both sides of the vane wrap with a 180 phase difference. This operating mechanism leads to alternating compression and discharge processes, which results in low torque variation. The orbiting compressor has been designed for an R410A residential air conditioner with a cooling capacity of 10.0 kW. The performance of the orbiting compressor model has been analytically investigated, where the volumetric, adiabatic and mechanical efficiencies were calculated to be 94.8%, 90.4% and 93.4%, respectively for the ARI condition. The EER was estimated to be about 10.86 with a motor efficiency of 89%. (author)

Modeling of a split type air conditioner with integrated water heater

International Nuclear Information System (INIS)

Techarungpaisan, P.; Theerakulpisut, S.; Priprem, S.

2007-01-01

This paper presents a steady state simulation model to predict the performance of a small split type air conditioner with integrated water heater. The mathematical model consists of submodels of system components such as evaporator, condenser, compressor, capillary tube, receiver and water heater. These submodels were built based on fundamental principles of heat transfer, thermodynamics, fluid mechanics, empirical relationships and manufacturer's data as necessary. The model was coded into a simulation program and used to predict system parameters of interest such as hot water temperature, condenser exit air temperature, evaporator exit air temperature, mass flow rate of refrigerant, heat rejection in the condenser and cooling capacity of the system. The simulation results were compared with experimental data obtained from an experimental rig built for validating the mathematical model. It was found that the experimental and simulation results are in good agreement

Performance assessment of adding Cu-ultrafine particles into falling film desiccant

International Nuclear Information System (INIS)

Al-Mulla Ali, A.

2006-01-01

The concept of dehumidification between air and liquid desiccant for the improvement of the efficiency of heating and cooling fluids in industrial applications was discussed. The use of solid/liquid desiccants has received much attention in recent years because liquid desiccants can take moisture from surrounding air at low temperature and then release the moisture at high temperature to provide a continuous process of dehumidification of air and regeneration of liquid desiccant. This process can be used with conventional vapor compression cycles. This paper presented a comparative numerical study between parallel and counter flow configurations that examined the effects of various parameters on heat and mass transfer for the dehumidification and cooling processes of air and regeneration rate of liquid desiccant. Ultrafine particles were added to the falling film desiccant to investigate heat and mass transfer enhancement for both parallel and counter flow channels. The Cu-volume fraction in the falling film desiccant and dispersion effect were the important parameters. A mathematical model was therefore developed to account for the addition of Cu-ultrafine particles into the film desiccant. The dehumidification and cooling rate processes were found to improve with an increase in the Cu-ultrafine particles and dispersion effect. The new hybrid AC system was shown to improve indoor air quality, reduce energy consumption, and be environmentally safe. It was concluded that although the volume fraction and dispersion factor improve the dehumidification and cooling processes of the air, the improvements are not significant due to the small thickness of the falling-film desiccant. The regeneration process did not improve for either controlling parameter because of the small thickness of the film desiccant. 14 refs., 10 figs

Thermoeconomic optimization of small size central air conditioner

International Nuclear Information System (INIS)

Zhang, G.Q.; Wang, L.; Liu, L.; Wang, Z.

2004-01-01

The application of thermoeconomic optimization design in an air-conditioning system is important in achieving economical life cycle cost. Previous work on thermoeconomic optimization mainly focused on directly calculating exergy input into the system. However, it is usually difficult to do so because of the uncertainty of input power of fan on the air side of the heat-exchanger and that of pump in the system. This paper introduces a new concept that exergy input into the system can be substituted for the sum of exergy destruction and exergy output from the system according to conservation of exergy. Although it is also difficult for a large-scale system to calculate exergy destruction, it is feasible to do so for a small-scale system, for instance, villa air conditioner (VAC). In order to perform thermoeconomic optimization, a program is firstly developed to evaluate the thermodynamic property of HFC134a on the basis of Martin-Hou state equation. Authors develop thermodynamic and thermoeconomic objective functions based on second law and thermoeconomic analysis of VAC system. Two optimization results are obtained. The design of VAC only aimed at decreasing the energy consumption is not comprehensive. Life cycle cost at thermoeconomic optimization is lower than that at thermodynamic optimization

Analysis of a variable speed air conditioner considering the R-290/POE ISO 22 mixture effect

International Nuclear Information System (INIS)

Ribeiro, Guilherme B.; Barbosa, Jader R.

2016-01-01

Highlights: • A numerical model that considers the oil-refrigerant mixture effect is proposed. • In order to compare the model, an air conditioner calorimeter was constructed. • The system was evaluated under oil circulation ratios between 1 and 7%. • The presence of oil resulted in a significant SEER deterioration (around 69%). - Abstract: Air-conditioning applications using propane (R-290) have several environmental and thermodynamic advantages over more commonly used refrigerants, such as R-410A and R-22. This paper presents the development of a mathematical model for variable capacity air conditioning systems that use R-290/POE ISO 22 as refrigerant/lubricant. The thermodynamic performance of the refrigeration system is evaluated in terms of the SEER (Seasonal Energy Efficiency Ratio). The thermodynamic properties of the refrigerant/lubricant mixture were obtained from a departure-function approach using the Peng-Robinson equation of state. The effect of the oil on the condenser and evaporator heat transfer coefficients and pressure drops was also taken into account. Sub-models were developed for each component of the air conditioning system, including the connecting lines and the scroll compressor. Furthermore, an air conditioner experimental calorimeter was constructed and tested in order to validate the proposed model.

Steady state modeling of desiccant wheels

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin Ryhl

2014-01-01

Desiccant wheels are rotary desiccant dehumidifiers used in air conditioning and drying applications. The modeling of simultaneous heat and mass transfer in these components is crucial for estimating their performances, as well as for simulating and optimizing their implementation in complete...

Experimental investigation of a novel configuration of desiccant based evaporative air conditioning system

International Nuclear Information System (INIS)

Uçkan, İrfan; Yılmaz, Tuncay; Hürdoğan, Ertaç; Büyükalaca, Orhan

2013-01-01

Highlights: ► A novel desiccant based evaporative cooling system is developed and tested. ► Cooling capacity, COP and energy consumption of the system are evaluated. ► Indoor air conditions are in the range of thermal comfort zone and expanded comfort zone. ► Designing of the system have considerable effect on the energy consumption. - Abstract: A novel configuration of desiccant based evaporative cooling system for air conditioning application is developed and tested. At the beginning of the design stage of the system, an analysis is carried out in order to maximize the performance of the system. It is found based on configuration that outdoor air must be used for regeneration to increase performance of the system and so three air channels are used. Experiments are carried out to investigate the total performance of the system and performance of the components used during summer season in a hot and humid climate. Effectiveness values for both heat exchangers and evaporative coolers are calculated through this work. In addition to the cooling capacity, coefficient of performance (COP) and energy consumption of the system are also evaluated. Results show that the effectiveness for the heat exchangers and evaporative coolers are very high under different outdoor conditions. It is also shown from the results that indoor air conditions are in the range of thermal comfort zone defined by ASHRAE and expanded comfort zone for evaporative air conditioning applications.

Natural refrigerants for air conditioners in passenger cars. A contribution to climate protection. Background; Natuerliche Kaeltemittel fuer PKW-Klimaanlagen. Ein Beitrag zum Klimaschutz. Hintergrund

Energy Technology Data Exchange (ETDEWEB)

Hoffmann, Gabriele; Plehn, Wolfgang

2010-09-15

Air conditioners in passenger cars contain a refrigerant which significantly increases the greenhouse effect. Currently about 30 % of global emissions of partially fluorinated hydrocarbons originate from these air conditioners. According to the directive 2006/40/EC, this refrigerant must be replaced by a less harmful substance. Under this aspect, the contribution under consideration initially reports on the stock and level of air conditioning of passenger cars as well as on the refrigerant tetrafluoroethane. Subsequently, refrigerants for air conditioning of passenger cars such as carbon dioxide, 1.1-difluoroethane and 2,3,3,3-tetrafluoro propylene are described. Overall, the refrigerant carbon dioxide is the best alternative for mobile air conditioning.

Field Demonstration of Active Desiccant-Based Outdoor Air Preconditioning Systems, Final Report: Phase 3; FINAL

International Nuclear Information System (INIS)

Fischer, J.

2001-01-01

This report summarizes an investigation of the performance of two active desiccant cooling systems that were installed as pilot systems in two locations-a college dormitory and a research laboratory-during the fall of 1999. The laboratory system was assembled in the field from commercially available Trane air-handling modules combined with a standard total energy recovery module and a customized active desiccant wheel, both produced by SEMCO. The dormitory system was a factory-built, integrated system produced by SEMCO that included both active desiccant and sensible-only recovery wheels, a direct-fired gas regeneration section, and a pre-piped Trane heat pump condensing section. Both systems were equipped with direct digital control systems, complete with full instrumentation and remote monitoring capabilities. This report includes detailed descriptions of these two systems, installation details, samples of actual performance, and estimations of the energy savings realized. These pi lot sites represent a continuation of previous active desiccant product development research (Fischer, Hallstrom, and Sand 2000; Fischer 2000). Both systems performed as anticipated, were reliable, and required minimal maintenance. The dehumidification/total-energy-recovery hybrid approach was particularly effective in all respects. System performance showed remarkable improvement in latent load handling capability and operating efficiency compared with the original conventional cooling system and with the conventional system that remained in another, identical wing of the facility. The dehumidification capacity of the pilot systems was very high, the cost of operation was very low, and the system was cost-effective, offering a simple payback for these retrofit installations of approximately 5 to 6 years. Most important, the dormitory system resolved numerous indoor air quality problems in the dormitory by providing effective humidity control and increased, continuous ventilation air

Developing a Standard Method of Test for Packaged, Solid-Desiccant Based Dehumidification Systems

International Nuclear Information System (INIS)

Sand, J.R.

2001-01-01

A draft Method of Test (MOT) has been proposed for packaged, air-to-air, desiccant-based dehumidifier systems that incorporate a thermally-regenerated desiccant material for dehumidification. This MOT is intended to function as the ''system'' testing and rating compliment to the desiccant ''component'' (desiccant wheels and/or cassettes) MOT (ASHRAE 1998) and rating standard (ARI 1998) already adopted by industry. This draft standard applies to ''packaged systems'' that: Use desiccants for dehumidification of conditioned air for buildings; Use heated air for regeneration of the desiccant material; Include fans for moving process and regeneration air; May include other system components for filtering, pre-cooling, post-cooling, or heating conditioned air; and May include other components for humidification of conditioned air. The proposed draft applies to four different system operating modes depending on whether outdoor or indoor air is used for process air and regeneration air streams . Only the ''ventilation'' mode which uses outdoor air for both process and regeneration inlets is evaluated in this paper. Performance of the dehumidification system is presented in terms that would be most familiar and useful to designers of building HVAC systems to facilitate integration of desiccant equipment with more conventional hardware. Parametric performance results from a modified, commercial desiccant dehumidifier undergoing laboratory testing were used as data input to evaluate the draft standard. Performance results calculated from this experimental input, results from an error-checking/heat-balance verification test built into the standard, and estimated comparisons between desiccant and similarly performing conventional dehumidification equipment are calculated and presented. Some variations in test procedures are suggested to aid in analytical assessment of individual component performance

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

Directory of Open Access Journals (Sweden)

Giovanni Angrisani

2016-09-01

Full Text Available In this paper, three alternative layouts (scenarios of an innovative solar-assisted hybrid desiccant-based air handling unit (AHU are investigated through dynamic simulations. Performance is evaluated with respect to a reference system and compared to those of the innovative plant without modifications. For each scenario, different collector types, surfaces and tilt angles are considered. The effect of the solar thermal energy surplus exploitation for other low-temperature uses is also investigated. The first alternative scenario consists of the recovery of the heat rejected by the condenser of the chiller to pre-heat the regeneration air. The second scenario considers the pre-heating of regeneration air with the warmer regeneration air exiting the desiccant wheel (DW. The last scenario provides pre-cooling of the process air before entering the DW. Results reveal that the plants with evacuated solar collectors (SC can ensure primary energy savings (15%–24% and avoid equivalent CO2 emissions (14%–22%, about 10 percentage points more than those with flat-plate collectors, when the solar thermal energy is used only for air conditioning and the collectors have the best tilt angle. If all of the solar thermal energy is considered, the best results with evacuated tube collectors are approximately 73% in terms of primary energy saving, 71% in terms of avoided equivalent CO2 emissions and a payback period of six years.

Efficient energy storage in liquid desiccant cooling systems

Energy Technology Data Exchange (ETDEWEB)

Hublitz, Astrid

2008-07-18

Liquid Desiccant Cooling Systems (LDCS) are open loop sorption systems for air conditioning that use a liquid desiccant such as a concentrated salt solution to dehumidify the outside air and cool it by evaporative cooling. Thermochemical energy storage in the concentrated liquid desiccant can bridge power mismatches between demand and supply. Low-flow LDCS provide high energy storage capacities but are not a state-of-the-art technology yet. The key challenge remains the uniform distribution of the liquid desiccant on the heat and mass transfer surfaces. The present research analyzes the factors of influence on the energy storage capacity by simulation of the heat and mass transfer processes and specifies performance goals for the distribution of the process media. Consequently, a distribution device for the liquid desiccant is developed that reliably meets the performance goals. (orig.)

Study on residential appliances energy efficiency standards Refrigerators, air-conditioners, incandescent lamps, fluorescent lamps, color TVs

Energy Technology Data Exchange (ETDEWEB)

Lee, S.G.; Cho, S.K.; Choi, S.H.; Jung, B.M.; Han, S.B.; Kim, K.D. [Korea Inst. of Energy Research, Taejon (Korea, Republic of)

1995-12-01

The energy efficiency standards and rating act, as amended by the rational energy utilization act, provides energy efficiency standards and ratings for 6 types of consumer products(refrigerators, air-conditioners, fluorescent lamps, incandescent lamps, ballasts and cars) authorizes the Ministry of Trade, Industry and Energy(MOTIE) to prescribe amended or new energy efficiency standards and rating standards. This study was initiated by the KIER in 1992. KIER`s assessment of the standards is designed to evaluate their statistical and engineering analysis according to Korean(Industrial) Standards(KS). And to make distinction between the poor efficiency and good efficiency models, 5 grades are classified depending on their tested energy efficiency. This year, based on our analysis, MOTIE mandated updated standards for refrigerators, air-conditioners, incandescent lamps, and fluorescent lamps. Also the objective of this study is to set the energy efficiency standards and to grade for color TV sets. (author). 37 refs., 89 figs., 85 tabs.

Development of a solar-powered residential air conditioner: Screening analysis

Science.gov (United States)

1975-01-01

Screening analysis aimed at the definition of an optimum configuration of a Rankine cycle solar-powered air conditioner designed for residential application were conducted. Initial studies revealed that system performance and cost were extremely sensitive to condensing temperature and to the type of condenser used in the system. Consequently, the screening analyses were concerned with the generation of parametric design data for different condenser approaches; i. e., (1) an ambient air condenser, (2) a humidified ambient air condenser (3) an evaporative condenser, and (4) a water condenser (with a cooling tower). All systems feature a high performance turbocompressor and a single refrigerant (R-11) for the power and refrigeration loops. Data were obtained by computerized methods developed to permit system characterization over a broad range of operating and design conditions. The criteria used for comparison of the candidate system approaches were (1) overall system COP (refrigeration effect/solar heat input), (2) auxiliary electric power for fans and pumps, and (3) system installed cost or cost to the user.

Accelerating Energy Efficiency Improvements in Room Air Conditioners in India: Potential, Costs-Benefits, and Policies

OpenAIRE

Abhyankar, N; Shah, N; Park, WY; Phadke, AA

2017-01-01

Rising incomes, increasing urbanization, and large cooling demand prompted by India’s hot, humid climate are driving increasing uptake of room air conditioners (ACs). Air conditioning already accounts for 40-60% of summer peak load in large Indian cities such as Delhi and is on track to contribute 140 gigawatts (GW) ( 30%) to peak demand in 2030. India’s standards and labeling policies improved the market average efficiency of room ACs by about 35% between 2006 and 2016 (3% per year) even as ...

Increased prevalence of IgG-induced sensitization and hypersensitivity pneumonitis (humidifier lung) in nonsmokers exposed to aerosols of a contaminated air conditioner.

Science.gov (United States)

Baur, X; Richter, G; Pethran, A; Czuppon, A B; Schwaiblmair, M

1992-01-01

Specific IgG antibodies against antigens of a contaminated air conditioner were estimated in serum of 134 workers of a printing company. Altogether 64% of the workers investigated revealed significantly elevated levels (> 3 U/ml) of IgG antibodies specific to these antigens as compared to a nonexposed control group. The occurrence of IgG antibodies for microbial extracts were 25% for Fusarium, 23% for Penicillium notatum, 13% for Alternaria tenuis, 12% for Aureobasidium pullulans, 9% for Sphaeropsidales species, 3% for Micropolyspora faeni, 2% for Aspergillus fumigatus and 2% for Thermoactionomyces vulgaris. Out of the 86 workers with elevated IgG antibodies for air conditioner antigens, 59 were nonsmokers. Considering a cut-off level of 10 U/ml IgG for high values, the proportion of smokers to nonsmokers becomes even more pronounced (6 to 36 respectively, binominal test p air conditioners are the best choice as antigen source for the diagnosis of humidifier lung in exposed workers. Nonsmokers are shown to have a high risk for immunological sensitization.

Performance of a prototype micro wind turbine in the manmade wind field from air conditioner of buildings

Directory of Open Access Journals (Sweden)

K. H. Goh

2012-03-01

Full Text Available Harnessing waste energy from the manmade air fields of buildings presents a new area of renewable energy to explore. Due to the unpredictability of the natural wind, this study is to evaluate the practicality for harnessing waste energy from the air conditioner exhaust units which are a more constant and predictable source available in the buildings. A prototype of the micro wind turbine has been designed to minimize the negative effect of the exhaust sources. After the micro wind turbine was manufactured, the performance of the turbine was tested in the selected air conditioner exhaust unit. Increasing the rotor solidity and decreasing the resistance of the generator contribute to improved starting torque and decreased generator break in torque respectively in the design. The power generation of the micro wind turbine increases with an increase of the rotor speed. The 24-hour operation of the prototype presents an observation for both exhaust performance and power generation prediction when the prototype is mounted on the exhaust unit.

Incidence of polybrominated diphenyl ethers in central air conditioner filter dust from a new office building

Energy Technology Data Exchange (ETDEWEB)

Ni Honggang; Cao Shanping; Chang Wenjing [Shenzhen Key Laboratory of Circular Economy, Shenzhen Graduate School, Peking University, Shenzhen 518055 (China); Zeng Hui, E-mail: huizeng0608@gmail.com [Shenzhen Key Laboratory of Circular Economy, Shenzhen Graduate School, Peking University, Shenzhen 518055 (China); Department of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing 100871 (China)

2011-07-15

This study examined polybrominated diphenyl ethers (PBDEs) in central air conditioner filter (CACF) dust from a new office building in Shenzhen, China. Human exposure to PBDE via dust inhalation and ingestion were also estimated. PBDEs level in CACF dust was lower than those in the other countries and regions. Approximately 0.671 pg/kg bw/day PM{sub 2.5} (Particulate Matter up to 2.5 {mu}m in size) bounded {Sigma}{sub 15}PBDEs can be inhaled deep into the lungs and 4.123 pg/kg bw/day PM{sub 10} (Particulate Matter up to 10 {mu}m in size) bounded {Sigma}{sub 15}PBDEs tend to be deposited in the upper parts of the respiratory system. The average total intake of {Sigma}{sub 15}PBDEs via dust inhalation and ingestion for adults reached {approx}141 pg/kg bw/day in this building. This value was far below the reference dose (RfD) recommended by United States Environmental Protection Agency. Human exposure to PBDEs via dust inhalation and ingestion in the new building is less than the old ones. - Highlights: > Human exposure to PBDEs via dust inhalation and ingestion in the new building is less than that in the old ones. > PBDE emissions from indoor sources can be expected to continue for a long time as the PBDE-containing products in offices were to be kept many years. > The household consumer products, especially computers, are the main sources of PBDEs in central air conditioner filter dust. > Further studies are needed to fully understand the emission mechanism of PBDE from indoor consumer products. - PBDEs in central air conditioner filter dust from a new building were investigated

Incidence of polybrominated diphenyl ethers in central air conditioner filter dust from a new office building

International Nuclear Information System (INIS)

Ni Honggang; Cao Shanping; Chang Wenjing; Zeng Hui

2011-01-01

This study examined polybrominated diphenyl ethers (PBDEs) in central air conditioner filter (CACF) dust from a new office building in Shenzhen, China. Human exposure to PBDE via dust inhalation and ingestion were also estimated. PBDEs level in CACF dust was lower than those in the other countries and regions. Approximately 0.671 pg/kg bw/day PM 2.5 (Particulate Matter up to 2.5 μm in size) bounded Σ 15 PBDEs can be inhaled deep into the lungs and 4.123 pg/kg bw/day PM 10 (Particulate Matter up to 10 μm in size) bounded Σ 15 PBDEs tend to be deposited in the upper parts of the respiratory system. The average total intake of Σ 15 PBDEs via dust inhalation and ingestion for adults reached ∼141 pg/kg bw/day in this building. This value was far below the reference dose (RfD) recommended by United States Environmental Protection Agency. Human exposure to PBDEs via dust inhalation and ingestion in the new building is less than the old ones. - Highlights: → Human exposure to PBDEs via dust inhalation and ingestion in the new building is less than that in the old ones. → PBDE emissions from indoor sources can be expected to continue for a long time as the PBDE-containing products in offices were to be kept many years. → The household consumer products, especially computers, are the main sources of PBDEs in central air conditioner filter dust. → Further studies are needed to fully understand the emission mechanism of PBDE from indoor consumer products. - PBDEs in central air conditioner filter dust from a new building were investigated

Temperature control of the four-zone split inverter air conditioners using LMI expression based on LQR for mixed H2/H∞

International Nuclear Information System (INIS)

Yang, YauBin; Wu, Min-Der; Chang, Yu-Choung

2014-01-01

Highlights: • The optimal control gains were obtained from the linear matrix inequalities with mixed H 2 and H ∞ control algorithm. • The proposed method guaranteed convergence, stability, and provided a way for disturbance rejection and energy savings. • The coupling effects occurred among the compressor speed, opening degrees, evaporator temperatures and superheats. • The system identification and thermal dynamics equations could obtain the inner and outer loop transfer functions. • All simulations in this paper were in discrete time domain. - Abstract: Air conditioners in either commercial or residential buildings consume substantial electricity. Enhancing the air conditioner efficiency by using a new control scheme is critical. In four-zone multi-evaporator air conditioner systems, coupling effects occur among the compressor speed, the degree of opening of the four electronic expansion valves, the temperatures of the four evaporators, and the four superheats. The system identification and thermodynamic equations could be used to obtain the inner and outer loop transfer functions between the air conditioner and its environment. A variable structure (switching) for the proportional integral anti-windup method could circumvent the saturation phenomenon generated from the integral controller. The optimal control gains were obtained from the linear matrix inequalities (LMI) based on a linear quadratic regulator (LQR) with a mixed H 2 and H ∞ control algorithm. In a simulated example, this efficient method, through those feedback gains, guaranteed convergence and stability. In addition, the results indicated that the proposed LMI using a mixed H 2 and H ∞ control method is also an alternative way for disturbance rejection and energy savings in buildings

Feasibility study of using agriculture waste as desiccant for air conditioning system

Energy Technology Data Exchange (ETDEWEB)

Khedari, J.; Rawangkul, R.; Hirunlabh, J. [King Mongkut' s University of Technology Thonburi, Bangkok (Thailand). Buidling Scientific Research Center; Chimchavee, W. [University of Thai Chamber of Commerce, Bangkok (Thailand); Watanasungsuit, A. [South East Asia Univ., Bangkok (Thailand). Engineering Management

2003-08-01

This research was aimed at investigating the feasibility of using dried agricultural waste as desiccant for an open cycle air conditioning system. The natural fibers are, therefore, intended to replace chemical desiccant such as silica gel, molecular sieves etc. The investigation was limited to Coconut coir (Cocos nucifera) and Durian peels (Durio zibethinus). Experimental results confirmed that dry coconut coir and durian peel can absorb 30 g and 17 g H{sub 2}O per 100 g dry product, respectively, from air at the average condition of 32{sup o}C and 75% relative humidity. The optimum airflow rate is about 84 and 98 m{sup 3}/hr-100 g dry product, respectively. Therefore, the dry coconut coir is more suitable than the dry durian peel. Comparison between the dry coconut coir and silica gel showed that the average adsorption rate of coconut coir is less than that of silica gel by about 5 g/h-100 g dry product at an airflow rate of 84 m{sup 3}/h and 60 min operating time. However, it is still an interesting option to replace silica gel in open cycle air conditioning system, as the decrease of average adsorption rate is rather small. The other extremely interesting advantage of coconut coir is that during moisture absorption the heat generated during the process is less important. That means the air leaves the coconut coir bed at a lower temperature compared to that with a silica gel. Therefore, the saving of cooling energy is much more important. (Author)

Performance study of a heat pump driven and hollow fiber membrane-based two-stage liquid desiccant air dehumidification system

International Nuclear Information System (INIS)

Zhang, Ning; Yin, Shao-You; Zhang, Li-Zhi

2016-01-01

Graphical abstract: A heat pump driven, hollow fiber membrane-based two-stage liquid desiccant air dehumidification system. - Highlights: • A two-stage hollow fiber membrane based air dehumidification is proposed. • It is heat pump driven liquid desiccant system. • Performance is improved 20% upon single stage system. • The optimal first to second stage dehumidification area ratio is 1.4. - Abstract: A novel compression heat pump driven and hollow fiber membrane-based two-stage liquid desiccant air dehumidification system is presented. The liquid desiccant droplets are prevented from crossing over into the process air by the semi-permeable membranes. The isoenthalpic processes are changed to quasi-isothermal processes by the two-stage dehumidification processes. The system is set up and a model is proposed for simulation. Heat and mass capacities in the system, including the membrane modules, the condenser, the evaporator and the heat exchangers are modeled in detail. The model is also validated experimentally. Compared with a single-stage dehumidification system, the two-stage system has a lower solution concentration exiting from the dehumidifier and a lower condensing temperature. Thus, a better thermodynamic system performance is realized and the COP can be increased by about 20% under the typical hot and humid conditions in Southern China. The allocations of heat and mass transfer areas in the system are also investigated. It is found that the optimal regeneration to dehumidification area ratio is 1.33. The optimal first to second stage dehumidification area ratio is 1.4; and the optimal first to second stage regeneration area ratio is 1.286.

Comparison of air conditioners for horticulture; Vergelijking van luchtbehandelingssystemen voor de tuinbouw

Energy Technology Data Exchange (ETDEWEB)

Knoll, B.; Hendriksen, L. [TNO, Delft (Netherlands)

2011-12-15

The desire to reduce energy consumption in the greenhouse sector results into new techniques and applications. As such air conditioners are applied in greenhouses. They serve to control temperature, relative humidity and air flow in the greenhouse. However, because of the totally different climatic conditions in the greenhouses such systems must be adapted. TNO investigates how the systems can be evaluated properly [Dutch] De wens om het energieverbruik in de glastuinbouw omlaag te brengen, leidt tot nieuwe technieken en toepassingen. Zo vinden in de utiliteit gangbare luchtbehandelingssystemen nu ook hun weg naar de kas. Ze dienen om temperatuur, relatieve luchtvochtigheid en luchtbeweging in de kas te beheersen. Maar vanwege de totaal andere klimaatomstandigheden moeten de systemen worden aangepast. TNO onderzoekt hoe de systemen goed kunnen worden geevalueerd.

Energy savings potential of a hybrid desiccant dehumidification air conditioning system in Beirut

International Nuclear Information System (INIS)

Ghali, Kamel

2008-01-01

In this work, the transient performance of a hybrid desiccant vapor compression air conditioning system is numerically simulated for the ambient conditions of Beirut. The main feature of this hybrid system is that the regenerative heat needed by the desiccant wheel is partly supplied by the condenser dissipated heat while the rest is supplied by an auxiliary gas heater. The hybrid air conditioning system of the present study replaces a 23 kW vapor compression unit for a typical office in Beirut characterized by a high latent load. The vapor compression subsystem size in the hybrid air conditioning system is reduced to 15 kW at the peak load when the regeneration temperature was fixed at 75 deg. C. Also the sensible heat ratio of the combined hybrid system increased from 0.47 to 0.73. Based on hour by hour simulation studies for a wide range of recorded ambient conditions of Beirut city, this paper predicts the annual energy consumption of the hybrid system in comparison with the conventional vapor compression system for the entire cooling season. The annual running costs savings for the hybrid system is 418.39 USD for a gas cost price of 0.141 USD/kg. The pay back period of the hybrid system is less than five years when the initial cost of the hybrid air conditioning system priced an additional 1712.00 USD. Hence, for a 20-year life cycle, the life cycle savings of the hybrid air conditioning system are 4295.19 USD

Study on the complexity pricing game and coordination of the duopoly air conditioner market with disturbance demand

Science.gov (United States)

Ma, Junhai; Xie, Lei

2016-03-01

The paper focuses on the dynamic pricing game of the duopoly air conditioner market with disturbance in demand and analyzes the influence of disturbance on the dynamic game system. Considering the demand for products, such as air conditioner, varies with different seasons, we assume three cases based on the condition of disturbance, including growth market (Case 1), declining market (Case 2) and completely random market (Case 3). By analyzing these three cases and making comparison among them, the paper shows that the growth market is more sensitive to the changing parameters such as the adjustment variable and the competitive factor than the declining market. It is more difficult to keep the system stable in a growth market. Although the demand is completely random, the dynamic system can reach a stable state, on condition that the adjustment variable is small enough. The results also indicate that the bullwhip effect between the order quantity and the actual demand is weakened gradually along with the price adjustment.

Investigation of the compressor part-load behaviour and its effects on the per annum energy consumption of the air conditioner; Untersuchung des Kompressor-Teillastverhaltens im Hinblick auf den Jahresverbrauch der Klimaanlage

Energy Technology Data Exchange (ETDEWEB)

Martin, Klaus; Lechner, Bernhard [Virtual Vehicle. Kompetenzzentrum - Das virtuelle Fahrzeug Forschungsgesellschaft mbH (ViF), Graz (Austria); Rieberer, Rene [Technische Univ. Graz (Austria); Moenkediek, Thomas [Audi AG, Ingolstadt (Germany)

2010-07-01

The air conditioning system is one of the most important ancillary units of a motor vehicle. Energetic optimization of air conditioners has been a key issue of research at AUDI AG during the past few years. As a rule, the cooling capacity of the air conditioner is controlled by adapting the compressor lift if the compressor is driven by the car engine and control via the rotational speed is not possible. As air conditioners ted to be designed for extreme conditions, the compressor will work at part load in most operating conditions. Optimization of the energetic efficiency of the air conditioner also means to look at the part-load behaviour of the compressor. Simulations have been used successfully by AUDI AG for many years now; the have helped to shorten development times and improve the product quality. The contribution describes an advanced model of a swivel plate compressor of a R134a cooling cycle with particular consideration of part-lift operation. The simulation model is based on measurements with continous recording of the piston lift. The focus is on the influence of reduced lift on the compressor efficiency. Another point of interest is the successful integration of the compressor model in the overall refrigerating cycle model which will be used for simulations of system performance and efficiency and for further optimization of the air conditioner. (orig.)

High Efficiency Room Air Conditioner

Energy Technology Data Exchange (ETDEWEB)

Bansal, Pradeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-01-01

This project was undertaken as a CRADA project between UT-Battelle and Geberal Electric Company and was funded by Department of Energy to design and develop of a high efficiency room air conditioner. A number of novel elements were investigated to improve the energy efficiency of a state-of-the-art WAC with base capacity of 10,000 BTU/h. One of the major modifications was made by downgrading its capacity from 10,000 BTU/hr to 8,000 BTU/hr by replacing the original compressor with a lower capacity (8,000 BTU/hr) but high efficiency compressor having an EER of 9.7 as compared with 9.3 of the original compressor. However, all heat exchangers from the original unit were retained to provide higher EER. The other subsequent major modifications included- (i) the AC fan motor was replaced by a brushless high efficiency ECM motor along with its fan housing, (ii) the capillary tube was replaced with a needle valve to better control the refrigerant flow and refrigerant set points, and (iii) the unit was tested with a drop-in environmentally friendly binary mixture of R32 (90% molar concentration)/R125 (10% molar concentration). The WAC was tested in the environmental chambers at ORNL as per the design rating conditions of AHAM/ASHRAE (Outdoor- 95F and 40%RH, Indoor- 80F, 51.5%RH). All these modifications resulted in enhancing the EER of the WAC by up to 25%.

Experimental study of regenerative desiccant integrated solar dryer with and without reflective mirror

Energy Technology Data Exchange (ETDEWEB)

Shanmugam, V. [Department of Mechanical Engineering, Sathyabama University, Chennai, 600 119 (India); Natarajan, E. [Institute for Energy Studies, College of Engineering, Anna University, Chennai, 600 025 (India)

2007-06-15

An indirect forced convection with desiccant integrated solar dryer has been built and tested. The main parts are: a flat plate solar air collector, a drying chamber, desiccant bed and a centrifugal blower. The system is operated in two modes, sunshine hours and off sunshine hours. During sun shine hours the hot air from the flat plate collector is forced to the drying chamber for drying the product and simultaneously the desiccant bed receives solar radiation directly and through the reflected mirror. In the off sunshine hours, the dryer is operated by circulating the air inside the drying chamber through the desiccant bed by a reversible fan. The dryer is used to dry 20 kg of green peas and pineapple slices. Drying experiments were conducted with and without the integration of desiccant unit. The effect of reflective mirror on the drying potential of desiccant unit was also investigated. With the inclusion of reflective mirror, the drying potential of the desiccant material is increased by 20% and the drying time is reduced. The drying efficiency of the system varies between 43% and 55% and the pick-up efficiency varies between 20% and 60%, respectively. Approximately in all the drying experiments 60% of moisture is removed by air heated using solar energy and the remainder by the desiccant. The inclusion of reflective mirror on the desiccant bed makes faster regeneration of the desiccant material. (author)

Performance comparison between a solar driven rotary desiccant cooling system and conventional vapor compression system (performance study of desiccant cooling)

International Nuclear Information System (INIS)

Ge, T.S.; Ziegler, F.; Wang, R.Z.; Wang, H.

2010-01-01

Solar driven rotary desiccant cooling systems have been widely recognized as alternatives to conventional vapor compression systems for their merits of energy-saving and being eco-friendly. In the previous paper, the basic performance features of desiccant wheel have been discussed. In this paper, a solar driven two-stage rotary desiccant cooling system and a vapor compression system are simulated to provide cooling for one floor in a commercial office building in two cities with different climates: Berlin and Shanghai. The model developed in the previous paper is adopted to predict the performance of the desiccant wheel. The objectives of this paper are to evaluate and compare the thermodynamic and economic performance of the two systems and to obtain useful data for practical application. Results show that the desiccant cooling system is able to meet the cooling demand and provide comfortable supply air in both of the two regions. The required regeneration temperatures are 55 deg. C in Berlin and 85 deg. C in Shanghai. As compared to the vapor compression system, the desiccant cooling system has better supply air quality and consumes less electricity. The results of the economic analysis demonstrate that the dynamic investment payback periods are 4.7 years in Berlin and 7.2 years in Shanghai.

Energy saving effect of desiccant ventilation system using Wakkanai siliceous shale

Science.gov (United States)

Nabeshima, Yuki; Togawa, Jun-ya; Nagano, Katsunori; Kazuyo, Tsuzuki

2017-10-01

The nuclear power station accident resulting from the Great East Japan Earthquake disaster has resulted in a constrained electricity supply. However, in this Asian region there is high temperature and high humidity and consequently dehumidification process requires a huge amount of energy. This is the reason for the increasing energy consumption in the residential and commercial sectors. Accordingly, a high efficiency air-conditioning system is needed to be developed. The desiccant ventilation system is effective to reduce energy consumption for the dehumidification process. This system is capable of dehumidifying without dew condensing unlike a conventional air-conditioning system. Then we focused on Wakkanai Siliceous Shale (WSS) as a desiccant material to develop a new desiccant ventilation system. This is low priced, high performance, new type of thing. The aim of this study is to develop a desiccant ventilation unit using the WSS rotor which can be regenerated with low-temperature by numerical calculation. The results of performance prediction of the desiccant unit, indicate that it is possible to regenerate the WSS rotor at low-temperature of between 35 - 45 °C. In addition, we produced an actual measurement for the desiccant unit and air-conditioning unit. This air-conditioning system was capable to reduce roughly 40 % of input energy consumption.

Innovative PCM-desiccant packet to provide dry microclimate and improve performance of cooling vest in hot environment

International Nuclear Information System (INIS)

Itani, Mariam; Ghaddar, Nesreen; Ghali, Kamel

2017-01-01

Highlights: • A PCM and desiccant packet is proposed for use in personal cooling vest to keep dry air next to skin. • A PCM-Desiccant model for clothed heated wet cylinder is developed and validated experimentally. • The microclimate air temperature was 0.6 °C higher in PCM-Desiccant case compared to PCM-only case. • Microclimate humidity content decreased due to desiccant from 21.23 to 19.74 g/kg dry air. • PCM melted fraction increased due to desiccant from 0.24 to 0.5. - Abstract: A novel combination of phase change material (PCM) and a solid desiccant layer is proposed for the aim of maintaining dry cool microclimate air adjacent to wet warm skin and hence improve PCM performance in cooling vests used in hot humid environment. A fabric-PCM-Desiccant model is developed to predict the temperature and moisture content of the microclimate air layer in the presence of a PCM-Desiccant packet. The developed model is validated through experiments conducted on a wet clothed heated cylinder for the two cases of using (i) a PCM only packet and (ii) a PCM-Desiccant packet. Microclimate air temperatures and humidity content as well as PCM and desiccant temperatures were measured experimentally and were compared with predicted values by the fabric-PCM-Desiccant model. Good agreement was attained with a maximum relative error of 7% in measured temperatures. A decrease is observed in the humidity content of the microclimate air in the presence of the solid desiccant from 21.23 g/kg dry air to 19.74 g/kg dry air and an increase in the melted fraction of the PCM at the end of the experiment from 0.24 to 0.5.

Experimental performance of indirect air–liquid membrane contactors for liquid desiccant cooling systems

International Nuclear Information System (INIS)

Das, Rajat Subhra; Jain, Sanjeev

2013-01-01

Owing to the stringent indoor air quality (IAQ) requirements and high cost of desiccants, one of the major concerns in liquid desiccant technology has been the carryover, which can be eliminated through indirect contact between desiccant and air. Membrane contactors using microporous semipermeable hydrophobic membranes have a great potential in this regard. This communication investigates the performance of semipermeable membrane based indirect contactors as dehumidifiers in liquid desiccant cooling applications. Experiments on different types of membrane contactors are carried out using lithium chloride (LiCl) solution as desiccant. The membrane contactors consist of alternate channels of air and liquid desiccant flowing in cross-flow direction. Hydrophobic membranes form a liquid tight, vapor permeable porous barrier between hygroscopic solution and moist air, thus eliminating carryover of desiccant droplets. In order to provide maximum contact area for air–desiccant interaction, a wicking material is sandwiched between two membranes in the liquid channel. It is observed that vapor flux upto 1300 g/m 2 h can be achieved in a membrane contactor with polypropylene (PP) membranes, although the dehumidification effectiveness remains low. The effect of key parameters on the transmembrane vapor transport is presented in the paper. - Highlights: • Indirect membrane contactors developed to avoid carryover in liquid desiccant system. • Dehumidification effectiveness and vapor flux reported under varying conditions. • Vapor flux upto 1295 g/m 2 h in polypropylene contactor with high area density. • Dehumidification effectiveness with LiCl solution varies within 23% to 45%

Optimum placement of condensing units of split-type air-conditioners by numerical simulation

Energy Technology Data Exchange (ETDEWEB)

Avara, Abdollah; Daneshgar, Ehsan [Mechanical Engineering Department, Persian Gulf University, Bushehr (Iran, Islamic Republic of)

2008-07-01

Split-type air-conditioners used in residential or office buildings often have the outdoor condensing units installed at the sidewalls or on the roofs. Installation distance from the supporting wall for the first group and the height of installation for the second group are two factors that affect the condenser efficiency. In this study, a CFD code is used to calculate the effect of distance from the supporting wall on the entrance air temperature and on the on-coil temperature of condenser installed between two walls. In the case of condenser installed on the roof, the effect of installation height of the condenser from the finished roof on on-coil temperature is investigated and the minimum recommended height of installation is determined. (author)

Select Components and Finish System Design of a Window Air Conditioner with Propane

Energy Technology Data Exchange (ETDEWEB)

Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-05-01

This report describes the technical targets for developing a high efficiency window air conditioner (WAC) using propane (R-290). The baseline unit selected for this activity is a GE R-410A WAC. We established collaboration with a Chinese rotary compressor manufacturer, to select an R-290 compressor. We first modelled and calibrated the WAC system model using R-410A. Next, we applied the calibrated system model to design the R-290 WAC, and decided the strategies to reduce the system charge below 260 grams and achieve the capacity and efficiency targets.

An experimental and theoretical study on an injection-assisted air-conditioner using R32 in the refrigeration cycle

International Nuclear Information System (INIS)

Qv, Dehu; Dong, Bingbing; Cao, Lin; Ni, Long; Wang, Jijin; Shang, Runxin; Yao, Yang

2017-01-01

Highlights: • An advanced injection-assisted air-conditioner (IAC) using R32 was proposed. • In the whole day-night cycle, cooling capacity and energy efficiency ratio of the IAC were enhanced dramatically. • The injection duration of 8 s maximized the IAC cooling potential. • Two-phase injection attained the highest exergetic efficiency approximating 50% or more. • The economic and environmental benefits of the IAC were demonstrated. - Abstract: An air-conditioner (AC) that uses refrigerant R32 assisted with one-phase vapor injection shows high energy efficiency and low discharge temperature in the heat-pump cycle, but the performance is not satisfactory in the refrigeration cycle. In this study, an improved injection cycle consisting of one-phase vapor injection mode and two-phase injection mode is proposed and integrated into an AC using R32, which is now referred to as an advanced injection-assisted air-conditioner (IAC). Through an experimental and theoretical study, an optimal injection duration of 8 s is attained for maximizing the refrigeration potential of the IAC. Furthermore, in an entire day–night cycle, both the cooling capacity and energy efficiency ratio (EER) of the IAC within the two-phase injection cycle are enhanced by 25% and 32%, respectively, compared with those of a noninjection-assisted AC. Moreover, two-phase injection offers the highest exergetic efficiency, approximately 50% or more in the refrigeration cycle, exhibiting remarkable thermodynamic performance of the IAC. In addition, compared to the conventional AC using R410A, the IAC using R32 within a two-phase injection cycle demonstrates reasonable payback performance and substantial reduction in carbon dioxide and sulfur dioxide emissions in the refrigeration cycle.

Effectiveness of finish materials and room air-conditioner on the reduction of indoor radon concentration in Hong Kong

International Nuclear Information System (INIS)

Ma, A.K.; Man, C.K.; Ho, E.; Pang, S.W.

1995-01-01

Four different kinds of finish material were investigated: wallpaper, paint, plaster and tile. When applied to the bare concrete walls of uninhabited rooms in flats of a building under construction, all of them were found to reduce indoor radon concentration. The magnitude of reduction by these finish materials ranged from 20% to 80%. Wallpaper was found to provide the best protection against radon emission from bare concrete walls in a bedroom with a size of 19.3 m 3 . Wallpaper can reduce the indoor radon concentration about twice as much as paint (water-based) or plaster in this investigation. Tile was also found to be a good material against radon emission from concrete walls in a bathroom with a size of 6.3 m 3 . Indoor radon concentration was found to decrease with elevation from the ground level, and was affected strongly by mechanical ventilation. Another 30% to 50% reduction in indoor radon concentration in addition to finish material can be achieved by a room air-conditioner. It was also found that indoor radon concentrations were not affected by turning the fresh air shutter to the 'on' or 'off' position in the room air-conditioner. (author)

A Proposal for the Time Domain Modeling of Split Air Conditioners for Consumer Reimbursement Studies

Science.gov (United States)

Rezende, Paulo Henrique Oliveira; Almeida Junior, Afonso Bernardino; Gondim, Isaque Nogueira; Oliveira, José Carlos

2015-04-01

This paper deals with computer application procedures for the evaluation of the causal consistency between anomalous phenomena manifested in electrical networks, along with the physical damage associated with electrical equipment and possible reimbursement requests. The focus is on the development of an air conditioner appliance model of the type known as split founded upon a representation, in the time domain, in accordance with the Alternative Transients Program (ATP) simulator requirements. This approach permits investigations concerning the performance of the product when submitted to ideal and non-ideal supply conditions. Once the equipment model is implemented in the program, a set of investigative studies are carried out to show the device performance under specific energy quality disturbance conditions. In addition, there are still the results for the validation of the process established through the correlation between computational performance of the air conditioner with corresponding studies carried out experimentally, which are presented herein. Moreover, once the effectiveness of the developed model is verified, it is implemented into the Requests for Reimbursement Software. Investigations related to the correlation between disturbances and the levels of thermal and dielectric tolerance are then performed aiming at illustrating the use of the research results for the reimbursement analyzes purposes.

Designing and testing the optimum design of automotive air-to-air thermoelectric air conditioner (TEAC) system

International Nuclear Information System (INIS)

Attar, Alaa; Lee, HoSung

2016-01-01

Highlights: • The optimum design of automotive thermoelectric AC system is proposed. • It is optimized by combining the thermal isolation and the dimensionless methods. • An experiment is conducted to validate the analytical design. - Abstract: The current project is discussing the optimization of counter flow air-to-air thermoelectric air conditioners (TEAC) system. Previous work showed an analytical model with experimental validation of a unit cell of TEAC system. However, the focus of this work is to simulate the optimum design of a whole TEAC system from given inlet parameters (i.e., hot and cold air mass flow rates and ambient temperatures). The analytical model was built by combining an optimal design method with dimensional analysis, which was recently developed, and the thermal isolation method in order to optimize the thermoelectric parameters (i.e., electrical current supplied and the number of thermocouples or the geometric factor, simultaneously). Moreover, based on the designed model, an experiment was conducted in order to study the accuracy of the analytical model. Even though the analytical model was built based on the thermoelectric ideal equations, it shows a good agreement with the experiment. This agreement was mainly a result of the use of the thermoelectric effective material properties which are obtained from the measured maximum thermoelectric module parameters. Since the experiment validate the analytical model, this model provides uncomplicated method to study the optimum design at given inputs.

Performance analysis of the electric vehicle air conditioner by replacing hydrocarbon refrigerant

Science.gov (United States)

Santoso, Budi; Tjahjana, D. D. D. P.

2017-01-01

The thermal comfort in passenger cabins needs an automotive air-conditioning system. The electric vehicle air conditioner system is driven by an electric compressor which includes a compressor and an electric motor. Almost air-conditioning system uses CFC-12, CFC-22 and HFC-134a as refrigerant. However, CFC-12 and CFC-22 will damage the ozone layer. The extreme huge global warming potentials (GWP) values of CFC-12, CFC-22, and HFC-134a represent the serious greenhouse effect of Earth. This article shows new experimental measurements and analysis by using a mixture of HC-134 to replace HFC-134a. The result is a refrigerating effect, the coefficient of performance and energy factor increase along with cooling capacity, both for HFC-134a and HC-134. The refrigerating effect of HC-134 is almost twice higher than HFC-134a. The coefficient of performance value of HC-134 is also 36.42% greater than HFC-134a. Then, the energy factor value of HC-134 is 3.78% greater than HFC-134a.

Numerical and experimental analysis of a solid desiccant wheel

Directory of Open Access Journals (Sweden)

Koronaki Irene P.

2016-01-01

Full Text Available The rotary desiccant dehumidifier is an important component which can be used in air conditioning systems in order to reduce the electrical energy consumption and introduce renewable energy sources. In this study a one dimensional gas side resistance model is presented for predicting the performance of the desiccant wheel. Measurements from two real sorption wheels are used in order to validate the model. One wheel uses silica gel as desiccant material and the other lithium chloride. The simulation results are in good agreement with the experimental data. The model is used to compare the counter flow with the co-current wheel arrangements and to explain why the counter flow one is more efficient for air dehumidification.

Development of a solar powered residential air conditioner (General optimization)

Science.gov (United States)

Lowen, D. J.

1976-01-01

A commercially available 3-ton residential Lithium Bromide (LiBr) absorption air conditioner was modified for use with lower temperature solar heated water. The modification included removal of components such as the generator, concentration control chamber, liquid trap, and separator; and the addition of a Chrysler designed generator, an off-the-shelf LiBr-solution pump. The design goal of the modified unit was to operate with water as the heat-transfer fluid at a target temperature of 85 C (185 F), 29.4 C (85 F) cooling water inlet, producing 10.5 kW (3 tons) of cooling. Tests were performed on the system before and after modification to provide comparative data. At elevated temperatures (96 C, 205 F), the test results show that Lithium Bromide was carried into the condenser due to the extremely violent boiling and degraded the evaporator performance.

Substantial energy conservation in air conditioners; Substantiele energiebesparing bij luchtbehandelingsinstallaties

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-03-01

An air conditioner has been retrofitted by application of an optimized fan in combination with an EC motor (brushless dc-motor). Attention is paid to the difference between an AC- and and EC motor, between free-running and spiral housing fans, between direct or indirect-driven, and between forward-bended and backward-bended blades. By means of equations and diagrams the realized energy conservation is visualized. [Dutch] De renovatie van een luchtbehandelingskast wordt besproken. Door de toepassing van ventilatoren met een geoptimaliseerde waaier in combinatie met een EC-motor (borstelloze gelijkstroommotor) wordt een substantiele energiebesparing gerealiseerd. Er wordt op verschillende aspecten ingegaan. Onder meer het verschil tussen een AC- en EC-motor, tussen vrijlopende en slakkenhuisventilatoren, tussen direct- of indirect-gedreven schoepen en tussen voorwaarts- of achterwaartsgebogen schoepen. Aan de hand van vergelijkingen en diagrammen wordt de energiewinst zichtbaar gemaakt.

High efficiency novel window air conditioner

International Nuclear Information System (INIS)

Bansal, Pradeep

2015-01-01

Highlights: • Use of novel refrigerant mixture of R32/R125 (85/15% molar conc.) to reduce global warming and improve energy efficiency. • Use of novel features such as electronically commuted motor (ECM) fan motor, slinger and sub-merged sub-cooler. • Energy savings of up to 0.1 Quads per year in USA and much more in Asia/Middle East where WACs are used in large numbers. • Payback period of only 1.4 years of the novel efficient WAC. - Abstract: This paper presents the results of an experimental and analytical evaluation of measures to raise the efficiency of window air conditioners (WAC). In order to achieve a higher energy efficiency ratio (EER), the original capacity of a baseline R410A unit was reduced by replacing the original compressor with a lower capacity but higher EER compressor, while all heat exchangers and the chassis from the original unit were retained. Subsequent major modifications included – replacing the alternating current fan motor with a brushless high efficiency electronically commutated motor (ECM) motor, replacing the capillary tube with a needle valve to better control the refrigerant flow and refrigerant set points, and replacing R410A with a ‘drop-in’ lower global warming potential (GWP) binary mixture of R32/R125 (85/15% molar concentration). All these modifications resulted in significant enhancement in the EER of the baseline WAC. Further, an economic analysis of the new WAC revealed an encouraging payback period

The design of the motor bracket for reduction of structure-borne noise in package air-conditioner

Energy Technology Data Exchange (ETDEWEB)

Sim, Hyoun Jin; Lee, Sung Jin; Oh, Jae Eung [Hanyang University, Seoul (Korea, Republic of); Kang, Tae Ho [WiniaMando, Asan (Korea, Republic of); Lee, Jung Yoon [Kyonggi University, Suwon (Korea, Republic of)

2006-02-15

As the economic power is improved and the customer's demand is hard to please, the noise and vibration is the most important yardstick that can determine the quality of the product. Especially, as the air-conditioner's demand increase suddenly, the product of quality and the noise is becoming a decisive factor of determining whether purchase the product or not. Therefore, every manufactory is investing a lot of money and research to cut down the unpleasantness induced from noise and vibration. And they are emphasizing their product's difference by advertising a silence very actively. With these reason, the demand of a silent indoor air-conditioner is the essential research filed when the product is developed. In this study, the noise and vibration is visualized in the space and frequency domain by using experimental methods such as Operational Deflection Shape (ODS), modal testing and sound intensity. Also the location of noise source and its characteristic is analyzed in an acoustical point of view to reduce the structure borne noise that come from the fan motor, and the pertinent control method is suggested. Furthermore, the most suitable shape of the motor bracket is suggested by applying FEM and DOE (Design of Experiments) in the noise and vibration point a view.

The design of the motor bracket for reduction of structure-borne noise in package air-conditioner

International Nuclear Information System (INIS)

Sim, Hyoun Jin; Lee, Sung Jin; Oh, Jae Eung; Kang, Tae Ho; Lee, Jung Yoon

2006-01-01

As the economic power is improved and the customer's demand is hard to please, the noise and vibration is the most important yardstick that can determine the quality of the product. Especially, as the air-conditioner's demand increase suddenly, the product of quality and the noise is becoming a decisive factor of determining whether purchase the product or not. Therefore, every manufactory is investing a lot of money and research to cut down the unpleasantness induced from noise and vibration. And they are emphasizing their product's difference by advertising a silence very actively. With these reason, the demand of a silent indoor air-conditioner is the essential research filed when the product is developed. In this study, the noise and vibration is visualized in the space and frequency domain by using experimental methods such as Operational Deflection Shape (ODS), modal testing and sound intensity. Also the location of noise source and its characteristic is analyzed in an acoustical point of view to reduce the structure borne noise that come from the fan motor, and the pertinent control method is suggested. Furthermore, the most suitable shape of the motor bracket is suggested by applying FEM and DOE (Design of Experiments) in the noise and vibration point a view

Feasibility study on an energy-saving desiccant wheel system with CO2 heat pump

Science.gov (United States)

Liu, Yefeng; Meng, Deren; Chen, Shen

2018-02-01

In traditional desiccant wheel, air regeneration process occurs inside an open loop, and lots of energy is consumed. In this paper, an energy-saving desiccant wheel system with CO2 heat pump and closed loop air regeneration is proposed. The general theory and features of the desiccant wheel are analysed. The main feature of the proposed system is that the air regeneration process occurs inside a closed loop, and a CO2 heat pump is utilized inside this loop for the air regeneration process as well as supplying cooling for the process air. The simulation results show that the proposed system can save significant energy.

Handling zone dividing method in packed bed liquid desiccant dehumidification/regeneration process

International Nuclear Information System (INIS)

Liu, X.H.; Jiang, Y.

2009-01-01

Dehumidifier and regenerator are the most significant components in liquid desiccant air-conditioning systems, in which air directly contacts liquid desiccant and heat and mass transfer process occurs between the two fluids. Heat transfer process and mass transfer process within dehumidifier/regenerator influence each other and should not be separately considered. Based on the previous reachable handling region analysis, a zonal method is proposed in present study. Four zones are divided in the psychrometric chart according to the relative position of inlet air to inlet desiccant including two dehumidification zones, zone A and zone D, and two regeneration zones, zone B and zone C. In zone A or C, mass transfer is key process, and counter-flow configuration has the best mass transfer performance and parallel-flow is the poorest in the same operating conditions. In zone B or D, heat transfer is governing process, parallel-flow has the best mass transfer performance and counter-flow is the poorest. In order to obtain better mass transfer performance, liquid desiccant should be cooled (in zone A) rather than air (in zone D) in dehumidifier, and liquid desiccant should be heated (in zone C) rather than air (in zone B) in regenerator. The divided zones and the corresponding zonal properties will be helpful to the design and optimization of dehumidifiers and regenerators.

Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners.

Science.gov (United States)

Batterman, S; Du, L; Mentz, G; Mukherjee, B; Parker, E; Godwin, C; Chin, J-Y; O'Toole, A; Robins, T; Rowe, Z; Lewis, T

2012-06-01

This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84±27%, but dropped to 63±33% in subsequent seasons. In months when households were not visited, use averaged only 34±30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions. Environmental tobacco smoke (ETS) increased particulate matter (PM) levels by about 14 μg/m3 and was often detected using ETS-specific tracers despite restrictions on smoking in the house as reported on questionnaires administered to caregivers. PM concentrations depended on season, filter usage, relative humidity, air exchange ratios, number of children, outdoor PM levels, sweeping/dusting, and presence of a central air conditioner (AC). Free-standing air filters can be an effective intervention that provides substantial reductions in PM concentrations if the filters are used. However, filter use was variable across the study population and declined over the study duration, and

Experimental analysis on performance of high temperature heat pump and desiccant wheel system

DEFF Research Database (Denmark)

Sheng, Ying; Zhang, Yufeng; Deng, Na

2013-01-01

In order to solve the problem of high energy consumption for regeneration of desiccant wheel in the rotary desiccant system, high temperature heat pump and desiccant wheel (HTHP&DW) system and corresponding air conditioning unit is built and tested in the extensive thermal hygrometric environment...

Energy performance of an innovative liquid desiccant dehumidification system with a counter-flow heat and mass exchanger using potassium formate

DEFF Research Database (Denmark)

Jradi, Muhyiddine; Riffat, Saffa

2014-01-01

An innovative micro-scale liquid desiccant dehumidification system is numerically investigated. The liquid desiccant dehumidification unit employs a counter-flow low-cost and efficient heat and mass exchange core, improving the thermal performance and eliminating desiccant carryover...... that the dehumidifier effectiveness is directly proportional to the intake air temperature, intake air relative humidity and liquid desiccant flow rate where the effectiveness is inversely proportional to the intake air velocity and the heat exchanger air channel height....

Evaluation of malodor for automobile air conditioner evaporator by using laboratory-scale test cooling bench.

Science.gov (United States)

Kim, Kyung Hwan; Kim, Sun Hwa; Jung, Young Rim; Kim, Man Goo

2008-09-12

As one of the measures to improve the environment in an automobile, malodor caused by the automobile air-conditioning system evaporator was evaluated and analyzed using laboratory-scale test cooling bench. The odor was simulated with an evaporator test cooling bench equipped with an airflow controller, air temperature and relative humidity controller. To simulate the same odor characteristics that occur from automobiles, one previously used automobile air conditioner evaporator associated with unpleasant odors was selected. The odor was evaluated by trained panels and collected with aluminum polyester bags. Collected samples were analyzed by thermal desorption into a cryotrap and subsequent gas chromatographic separation, followed by simultaneous olfactometry, flame ionization detector and identified by atomic emission detection and mass spectrometry. Compounds such as alcohols, aldehydes, and organic acids were identified as responsible odor-active compounds. Gas chromatography/flame ionization detection/olfactometry combined sensory method with instrumental analysis was very effective as an odor evaluation method in an automobile air-conditioning system evaporator.

Energy savings and economics of advanced control strategies for packaged air conditioners with gas heat

Energy Technology Data Exchange (ETDEWEB)

Wang, Weimin; Katipamula, Srinivas; Huang, Yunzhi; Brambley, Michael R.

2013-10-01

This paper presents an evaluation of the potential energy savings from adding advanced control to existing packaged air conditioners. Advanced control options include air-side economizer, multi-speed fan control, demand control ventilation and staged cooling. The energy and cost savings from the different control strategies individually and in combination are estimated using the EnergyPlus detailed energy simulation program for four building types, namely, a small office building, a stand-alone retail building, a strip mall building and a supermarket building. For each of the four building types, the simulation was run for 16 locations covering all 15 climate zones in the U.S. The maximum installed cost of a replacement controller that provides acceptable payback periods to owners is estimated.

Desiccation: An environmental and food industry stress that bacteria commonly face.

Science.gov (United States)

Esbelin, Julia; Santos, Tiago; Hébraud, Michel

2018-02-01

Water is essential for all living organisms, for animals as well as for plants and micro-organisms. For these latter, the presence of water or a humid environment with a high air relative humidity (RH) is necessary for their survival and growth. Thus, variations in the availability of water or in the air relative humidity constitute widespread environmental stresses which challenge microorganisms, and especially bacteria. Indeed, in their direct environment, bacteria are often faced with conditions that remove cell-bound water through air-drying of the atmosphere. Bacterial cells are subject to daily or seasonal environmental variations, sometimes going through periods of severe desiccation. This is also the case in the food industry, where air dehumidification treatments are applied after the daily cleaning-disinfection procedures. In plants producing low-water activity products, it is also usual to significantly reduce or eliminate water usage. Periodic desiccation exposure affects bacteria viability and so they require strategies to persist. Negative effects of desiccation are wide ranging and include direct cellular damage but also changes in the biochemical and biophysical properties of cells for which planktonic cells are more exposed than cells in biofilm. Understanding the mechanisms of desiccation adaptation and tolerance has a biological and biotechnological interest. This review gives an overview of the factors influencing desiccation tolerance and the biological mechanisms involved in this stress response. Copyright © 2017 Elsevier Ltd. All rights reserved.

Desiccant Dewpoint Cooling System Independent of External Water Sources

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Markussen, Wiebke B.

2015-01-01

the air that regenerates the desiccant dehumidifier, and using it for running the evaporative coolers in the system. A closed regeneration circuit is used for maximizing the amount of condensed water. This solution is applied to a system with a desiccant wheel dehumidifier and a dew point cooler, termed...... desiccant dew-point cooling system, for demonstrating its function and applicability. Simulations are carried out for varying outdoor conditions under constant supply conditions. The results show that the system is independent of external water supply for the majority of simulated conditions. In comparison...... to the desiccant dew-point system without water recovery, the required regeneration temperature increases and the system thermal efficiency decreases....

The experimental investigation of refrigerant distribution and leaking characteristics of R290 in split type household air conditioner

International Nuclear Information System (INIS)

Tang, Weier; He, Guogeng; Cai, Dehua; Zhu, Yihao; Zhang, Aoni; Tian, Qiqi

2017-01-01

Highlights: • A new quasi-liquid nitrogen method (QLNM) was proposed and firstly applied in experiments. • The R290 distribution was investigated by QLNM and the results proved the validation. • A solenoid valve was proposed to install near the capillary in STHAC in order to reduce risk factor. • R290 leaking rate was firstly measured by QLNM before and after the installation a solenoid valve. - Abstract: As a high-profile replacement for R22 split type household air conditioner (STHAC), R290 has several advantages in terms of thermodynamic properties, environmental characteristics, and cost. However, the obvious shortcoming of R290 is its flammability, which has a potential fire risk to the building. At present, the most important measure to ensure the safety of a R290 STHAC is to limit the refrigerant charge by domestic and international standards. But in fact, when the leakage of R290 occur from a STHAC, the distribution of R290 in STHAC, and the leaking rate also will seriously affect the safety of an R290 STHAC. In this study, a new quasi-liquid nitrogen method (QLNM) has been proposed in order to investigate the refrigerant distribution in R290 STHACs and the leaking rate under various conditions, and the experiments have been conducted. The experimental results of distribution proved the validation of the QLNM and showed that a large portion of the refrigerant distributed in the condenser when the air conditioner is on running stage and the refrigerant will migrate from the condenser to the evaporator when the air conditioner is on closed stage. Based on this, the installation of a solenoid valve near the capillary has been proposed. The comparison of experimental results of R290 leaking rate before and after the installation of a solenoid valve showed it will obviously reduce the leaking rate and thereby improve the safety of the R290 STHACs.

Experimental study on mass transfer performances of cross flow dehumidifier using liquid desiccant

International Nuclear Information System (INIS)

Liu, X.H.; Zhang, Y.; Qu, K.Y.; Jiang, Y.

2006-01-01

The liquid desiccant air conditioning system is drawing more and more attention due to its advantages in energy saving and environmental friendliness. The dehumidifier is one of the essential parts of the system, which affects the whole system performance severely. This paper experimentally studies the performance of the cross flow dehumidifier, which has been less studied than the counter flow dehumidifier, although it is more applicable in practice. Celdek structured packings were used in the dehumidifier, and a LiBr aqueous solution was used as the liquid desiccant. The moisture removal rate and dehumidifier effectiveness were adopted as the dehumidifier performance indices. The effects of the dehumidifier inlet parameters, including air and desiccant flow rates, air inlet temperature and humidity ratio and desiccant inlet temperature and concentration, on the two indices were investigated. Correlations are proposed to predict the cross flow dehumidifier performance, which give results in good agreement with the present experimental findings

Vacuum membrane distillation of liquid desiccants Utilizing Hollow Fiber Membranes

KAUST Repository

Lefers, Ryan

2018-01-31

This paper documents the testing of a vacuum membrane distillation system intended for use with liquid desiccants. Liquid desiccants offer the possibility for low-energy, ambient temperature dehumidification. Effective desalination and purification of diluted desiccants outputs two important products: a concentrated desiccant for reuse in dehumidification and fresh water. In this study, vacuum membrane distillation was used in the laboratory to purify diluted liquid desiccants. Calcium chloride and magnesium chloride were the desiccants selected for testing. Desiccant solutions were pumped through the lumens of poly(vinylidene fluoride) (PVDF) hollow fiber membranes at varying feed inlet temperatures, solution velocity rates and vacuum set points during membrane distillation. An average flux of 8 kg m-2 h-1 was obtained using 30 wt% magnesium chloride solution at a temperature of 50 °C while applying vacuum to achieve 25 mbar absolute pressure on the air side of the membrane. The results are promising for the development of a full-scale vacuum membrane distillation process for desiccant solution regeneration and fresh water recovery. In addition, the recovered condensate was of sufficient quality for use in agricultural irrigation or drinking water.

Vacuum membrane distillation of liquid desiccants Utilizing Hollow Fiber Membranes

KAUST Repository

Lefers, Ryan; Srivatsa Bettahalli, N.M.; Fedoroff, Nina V.; Nunes, Suzana Pereira; Leiknes, TorOve

2018-01-01

This paper documents the testing of a vacuum membrane distillation system intended for use with liquid desiccants. Liquid desiccants offer the possibility for low-energy, ambient temperature dehumidification. Effective desalination and purification of diluted desiccants outputs two important products: a concentrated desiccant for reuse in dehumidification and fresh water. In this study, vacuum membrane distillation was used in the laboratory to purify diluted liquid desiccants. Calcium chloride and magnesium chloride were the desiccants selected for testing. Desiccant solutions were pumped through the lumens of poly(vinylidene fluoride) (PVDF) hollow fiber membranes at varying feed inlet temperatures, solution velocity rates and vacuum set points during membrane distillation. An average flux of 8 kg m-2 h-1 was obtained using 30 wt% magnesium chloride solution at a temperature of 50 °C while applying vacuum to achieve 25 mbar absolute pressure on the air side of the membrane. The results are promising for the development of a full-scale vacuum membrane distillation process for desiccant solution regeneration and fresh water recovery. In addition, the recovered condensate was of sufficient quality for use in agricultural irrigation or drinking water.

A review on test procedure, energy efficiency standards and energy labels for room air conditioners and refrigerator-freezers

Energy Technology Data Exchange (ETDEWEB)

Mahlia, T.M.I.; Saidur, R. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2010-09-15

Air conditioners and refrigerator-freezers are major energy users in a household environment and hence efficiency improvement of these appliances can be considered as an important step to reduce their energy consumption along with environmental pollution prevention. Energy efficiency standards and labels are commonly used tools to reduce the energy uses for household appliances for many countries around the world. The first step towards adopting energy efficiency standards is to establish a test procedure for rating and testing of an appliance. It may be mentioned that an energy test procedure is the technical foundation for energy efficiency standards, energy labels, and other related programs. This paper reviews requirements and specifications of various international test standards for testing and rating of room air conditioners and refrigerators. A review on the development of the energy efficiency standards has been provided as well. Finally, energy labels that provide some useful information for identifying energy efficient products have been reviewed for these appliances. It may be stated that the review will be useful for the developing countries who wish to develop these energy savings strategies. It is also expected to be useful to revise the existing strategies for a few selected countries who already implemented these strategies earlier. (author)

The effects of regeneration temperature of the desiccant wheel on the performance of desiccant cooling cycles for greenhouse thermally insulated

Science.gov (United States)

Rjibi, Amel; Kooli, Sami; Guizani, Amenaallah

2018-05-01

The use of solar energy for cooling greenhouses in the hot period in Mediterranean climate is an important issue. Desiccant evaporative cooling (DEC) system is advantageous because it uses a low grade thermal energy and preserves the merits to be friendly environmentally technology. In this paper, a numerical investigation was carried out on a desiccant cooling system powered by air solar collectors coupled to an insulated greenhouse. The influence of the regeneration temperature on the air stream properties at every system component state point was studied. The performance of the desiccant cooling system was evaluated in terms of thermal and electric coefficient of performance. Results show that the best performance of the system (COPel = 14 and COPth = 0.94) was obtained for a 60 °C regeneration temperature and a supply flow rate ratio of 0.2. An economic analysis shows that the use of the DEC system for greenhouse cooling is attractive and profitable since the payback period is 1 years. The use of the proposed system allows saving 9396 kWh/year of electric energy compared to conventional system.

Study on load levelling by means of the control of air conditioner operation; Kuchoki kado seigyo ni yoru fuka heijunka ni kansuru ichikosatsu

Energy Technology Data Exchange (ETDEWEB)

Sasaki, H. [Hiroshima University, Hiroshima (Japan); Sadakuni, S. [Japan Broadcasting Corp., Tokyo (Japan)

1995-04-20

The recent drastic increase in the number of air conditioners has caused sharp and narrow peaks in summer seasons due to the inherent temperature sensitive characteristics. The authors proposed to reduce the peak power demand by controlling air conditioner operations, verifying its effectiveness on peak demand clipping. However, the former study has shortcomings in that any qualitative treatment of room temperatures or pleasant feeling was not attempted and it did not provide a way of assessing peak demand clipping in a power system as a whole. In this paper, we shall first propose a new control method that can compromise pleasant feeling and reduction in power demand. Although air conditioners are used to pursue `pleasant feeling`, this contradicts to reduce power consumption and further more the concept of `pleasant feeling` is very vague. Hence, `Weber-Fechner`s law` is utilized to quantify the pleasant feeling which is treated as fuzzy quantity. Fuzzy co-ordination method is used to compromise power demand curtailment and pleasantness. In the second part of this paper, we shall propose an approach of assessing the amount of peak load clipping when the newly proposed control strategy is adopted in a real size power system: A decrease in the required generation capacity is estimated provided that the Loss of Load Probability (LOLP) is maintained at the same level before and after the application of the new control strategy. The reduction can be regarded as a dividend of load management. 5 refs., 9 figs., 5 tabs.

Research and development needs for desiccant cooling technology 1992--1997. (Supplement to the NREL report, Desiccant Cooling: State-of-the-Art Assessment)

Energy Technology Data Exchange (ETDEWEB)

Pesaran, A A

1992-12-01

This report is a supplement to Desiccant Cooling: State-of-the-Art Assessment (NREL/TP-254-4147, DE93000013). In this supplement document we have described a detailed program assuming sufficient funding to implement the R&D activities needed. Desiccant dehumidification is a mature technology for industrial applications, and in recent years the technology has been used for air conditioning a number of institutional and commercial buildings. Our proposal is based on argumentative discussions at various national meetings with leaders of the technology. The goal is the penetration of the broad air conditioning market. This work is funded by the Buildings technology Office of the US Department of Energy.

Efficiency and limitations of the upper airway mucosa as an air conditioner evaluated from the mechanisms of bronchoconstriction in asthmatic subjects.

Science.gov (United States)

Konno, A; Terada, N; Okamoto, Y; Togawa, K

1985-01-01

To elucidate a limit to the efficiency of the upper airway mucosa as an air conditioner, the temperatures of the inspiratory air and mucosa were measured in the cervical trachea. Both of them were affected only minimally by change of atmospheric air temperature during resting nose breathing, but were affected greatly by change of mode of breathing. During hyperventilation through the mouth, when the atmospheric air temperature was 1 degree C, a temperature difference of 9 degrees C was noted between inspiratory air in the cervical trachea and body temperature, together with a mucosal temperature fall by 1.86 +/- 0.61 degree C. Wearing of a mask caused a rise of 3 degrees C in the inspiratory air temperature in the cervical trachea.

Soil desiccation cracks as a suction–contraction process

KAUST Repository

Cordero, J. A.; Useche, G.; Prat, P. C.; Ledesma, A.; Santamarina, Carlos

2017-01-01

Recent macro- and particle-scale advances in unsaturated soil behaviour have led to an enhanced understanding of the effects of moisture changes on soil response. This research examines desiccation cracks as a suction–contraction-coupled process using sand–clay mixtures. Suction–moisture measurements highlight the role of fines on suction potential even at low fines content; on the other hand, oedometer tests exhibit a marked transition from sand-controlled to clay-controlled compressibility. Time-lapse photography of desiccation tests in flat trays show the onset of crack initiation and the subsequent evolution in horizontal strains; concurrent gravimetric water content measurements relate crack nucleation to suction at air entry. Suction and compressibility increase with the soil-specific surface and have a compounded effect on desiccation-driven lateral contraction. Both layer thickness and its lateral extent affect the development of desiccation cracks. The recently proposed revised soil classification system properly anticipates the transitions in compressibility and capillary phenomena observed in this study (between 15 and 35% fines content).

Soil desiccation cracks as a suction–contraction process

KAUST Repository

Cordero, J. A.

2017-10-05

Recent macro- and particle-scale advances in unsaturated soil behaviour have led to an enhanced understanding of the effects of moisture changes on soil response. This research examines desiccation cracks as a suction–contraction-coupled process using sand–clay mixtures. Suction–moisture measurements highlight the role of fines on suction potential even at low fines content; on the other hand, oedometer tests exhibit a marked transition from sand-controlled to clay-controlled compressibility. Time-lapse photography of desiccation tests in flat trays show the onset of crack initiation and the subsequent evolution in horizontal strains; concurrent gravimetric water content measurements relate crack nucleation to suction at air entry. Suction and compressibility increase with the soil-specific surface and have a compounded effect on desiccation-driven lateral contraction. Both layer thickness and its lateral extent affect the development of desiccation cracks. The recently proposed revised soil classification system properly anticipates the transitions in compressibility and capillary phenomena observed in this study (between 15 and 35% fines content).

Effect of inter-cooling on the performance and economics of a solar energy assisted hybrid air conditioning system with six stages one-rotor desiccant wheel

International Nuclear Information System (INIS)

Elzahzby, Ali M.; Kabeel, A.E.; Bassuoni, M.M.; Abdelgaied, Mohamed

2014-01-01

Highlights: • Development of a mathematical model for predicting the performance of solar energy assisted hybrid air conditioning system. • The model uses a one-rotor six-stage rotary silica gel desiccant wheel. • Theoretical model results are in good agreement with experimental data. • The influences of main operating parameters on optimal rotational speed are discussed. • A life cycle cost analysis of the proposed system has been investigated. - Abstract: In this study, a mathematical model for predicting the performance of solar energy assisted hybrid air conditioning system (SEAHACS) was considered. The desiccant wheels used honeycombed silica gel–haloids composite material. This one-rotor desiccant wheel is divided into six stages, in which two-stage dehumidification process, two-stage pre-cooling process and two-stage regeneration process are realized. Three air streams are involved in the present system. The mathematical model has been validated with the experimental data. As the key operating and design parameter, the range of process air inlet temperature from 27.5 to 45 °C, range of humidity ratio of the inlet process air from 9 to 21 g/kg, process air inlet velocity from 1.5 to 5.5 m/s have been examined for a range of rotation speed from 6 to 20 rev/h. the optimization of this parameters is conducted based on the moisture removal capacity D, relative moisture removal capacity, dehumidification coefficient of performance, thermal coefficient of performance, and supply air temperature and humidity ratio. At last, the influences of these main parameters on optimal rotational speed are discussed. Eventually, the life cycle cost analysis of the solar energy assisted hybrid air conditioning system has been investigated

Effects of ejector geometries on performance of ejector-expansion R410A air conditioner considering cooling seasonal performance factor

International Nuclear Information System (INIS)

Jeon, Yongseok; Jung, Jongho; Kim, Dongwoo; Kim, Sunjae; Kim, Yongchan

2017-01-01

Highlights: •The performance of an ejector-expansion R410A air conditioner is measured. •The effect of ejector geometries on the COP and CSPF is analyzed. •The mixing-section diameter of the ejector is optimized based on the CSPF. •The mixing-section diameter is optimized based on the climatic conditions. -- Abstract: The objective of this study was to investigate the effects of ejector geometries on the performance of an ejector-expansion air conditioner (EEAC) considering the cooling seasonal performance factor (CSPF). The performance of the EEAC using R410A was measured and analyzed by varying the compressor speed, outdoor-bin temperature, operating pressures, nozzle-throat diameter, and mixing-section diameter. The EEAC in the medium-capacity mode exhibited maximum coefficient of performance (COP) improvement, i.e., 7.5%, over the baseline (conventional) cycle. The optimum mixing-section diameter was determined to be 9 mm based on the CSPF. In addition, the optimum mixing-section diameter increased with an increase in the annual average outdoor temperature. The CSPF of the EEAC with the optimized mixing-section diameter improved in the range of 16.0–20.3% over the baseline cycle depending on the climatic conditions.

Formulation and validation of a two-dimensional steady-state model of desiccant wheels

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin R.

2015-01-01

Desiccant wheels are rotary desiccant dehumidifiers used in air-conditioning and drying applications. The modeling of simultaneous heat and mass transfer in these components is crucial for estimating their performances, as well as for simulating and optimizing their implementation in complete...

Cyclic crack resistance of magnesium alloys in vacuum, humid an highly desiccated air

International Nuclear Information System (INIS)

Yarema, S.Ya.; Zinyuk, O.D.

1986-01-01

Investigation results on cyclic crack resistance of four structural magnesium alloys in vacuum, humid and highly desiccated air are presented. The regularities obtained are discussed at the background of the known data, using the data on crack closing and hydrogen concenration near its vertex. Diagrams of fatigue fracture of magnesium alloys MA2-1, MA15, MA8 and MA18, produced in vacuum, dry and humid air, on the whole obey the previously established regularities for aluminium alloys and steels. The diagrams of fatigue fracture plotted taking into account crack closing (v-ΔK eff ) for dry and humid air are quite similar. An increase in cyclic crack resistance of the materials in vacuum can not be explained by the change in the crack closing and is evidently conditioned by the absence of hydrogen absorption as the main factor accelerating the crack growth. Effect of vacuum on the threshold K th increases with the increase in σ 0.2 , which testifies to a strong effect of medium on the rate of fatigue crack growth in near the threshold region

Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Rooftop Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Bargach, Youssef [Navigant Consulting Inc., Burlington, MA (United States)

2016-09-01

The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for Low-Global Warming Potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants relative to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in packaged or Rooftop Unit (RTU) air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerants selection process, the test procedures, and the final results.

Solar assisted liquid desiccant cooling using clay based membranes

Directory of Open Access Journals (Sweden)

Priya S. Shanmuga

2018-01-01

Full Text Available The environmental concerns have led to the urge of the usage of non-conventional energy resources like solar, wind, thermal, geothermal etc. which provide enormous source of energy without causing any further diminution of the environment. Instead of the conventional HVAC systems that cause colossal environmental perils, usage of liquid desiccants in coming in vogue whereby reducing ecological threats. Moreover, solar assisted systems provide further impulse to such systems. This paper discusses about the various comparisons between liquid desiccants: Lithium chloride, Potassium formate and Calcium chloride and concludes that potassium formate is the best desiccant to be used among the three. Potassium formate (HCOOK is used which is cheaper and less corrosive as compared to the other aqueous salts, and has a negative crystallization temperature. Potassium formate is a new liquid desiccant and thus, not much research is available currently. The weather conditions of Manipal provide an appropriate condition for the experimentations of solar aided liquid desiccant evaporative cooling systems due to its humid climate and intense solar radiation obtained. The small scale experimentation also encounters the problem of liquid desiccant carryover by the air flow, with the help of clay based membranes which are again cheap, environmentally benign and obtained in a facile way. The projected system takes complete advantage of pure solar energy aimed at the regeneration of liquid desiccant.

Locating room air-conditioners at floor level for energy saving in residential buildings

International Nuclear Information System (INIS)

Gao, C.F.; Lee, W.L.; Chen Hua

2009-01-01

Residential air-conditioning becomes a common feature in our daily life. They are typically installed at high level known as ceiling-based system (CAC). With the increasing use of floor-based air-conditioning system in commercial buildings for energy saving, it is proposed in this study to locate a top discharge/front return air-conditioner at floor level to resemble a floor-based air-conditioning system (FAC) to curb energy use in residential buildings. Given the concerns about draught discomfort and thermal stratification associated with floor-based air-conditioning systems, the objective of this study is to evaluate the air distribution performance and to quantify the possible energy benefits. Bedroom was chosen as a sensitive case for detailed air distribution performance evaluation. Experimental study, CFD simulations and energy simulations were conducted in achieving the specific objectives. CAC and FAC were installed in a bedroom-like environmental chamber for experimental study at different indoor and outdoor conditions. The air velocities and temperatures at various positions and levels inside the chamber were measured to determine the air distribution performance indices (ADPI) and airflow draft risk (DR). The cooling output, power consumption and coefficient of performance (COP) of the two units were measured and calculated for comparison. The experimental results show that ADPI of CAC and FAC are 92.3% and 84.6%, respectively. COP of FAC is 8.11% higher than CAC, and the corresponding DR are comparable. The experimental results were used to validate the CFD simulations as well as providing actual performance data for predicting the energy use of applying CAC and FAC in a case-study building. CFD simulations and draught assessment confirmed that there is no potential draught discomfort and thermal stratification associated with the use of FAC. Energy simulations predicted that the associated energy saving is 6.9%. Wider use of FAC in residential

Simulation of potential standalone liquid desiccant cooling cycles

International Nuclear Information System (INIS)

Das, Rajat Subhra; Jain, Sanjeev

2015-01-01

LDCS (Liquid desiccant cooling systems), capable of achieving dehumidification and cooling with low-grade heat input, can be effectively used for treating fresh air in hot and humid regions. These can also be operated using non-concentrating solar collectors. The present study is concerned with the evaluation of various potential liquid desiccant cycles for tropical climatic conditions. Six potential standalone liquid desiccant cycles are identified and analyzed to select the best configuration for achieving thermal comfort. A computer simulation model is developed in EES (Equation Solver) software platform to evaluate the performance of all the cycles at various operating conditions. Aqueous solution of LiCl (lithium chloride) is used as desiccant. Mass and energy balance equations of all the components along with their effectiveness and LiCl property correlation equations are solved simultaneously for given ambient conditions. As the desiccant circuit is a closed loop, no assumptions are made about its concentration and temperature in the algorithm. Supply air conditions, cooling capacity, COP (capacity and coefficient of performance) and CR (circulation rate) per unit cooling capacity and hot water temperature requirement are used as a measure for analyzing the performance of the different cycles. The effect of hot water temperature on the performance of the cycles is evaluated at ARI conditions. The performances of the cycles are also evaluated for cities selected from each of the climatic zone of India that represent typical tropical climates. Although all the cycles are feasible at ARI and hot and dry conditions, only two cycles can achieve the selected indoor conditions in the peak humid conditions. The results would be useful for selecting suitable liquid desiccant cycle for a given climate. - Highlights: • Six potential standalone liquid desiccant cycles identified and analyzed to select best configuration. • A computer simulation model is developed in

Elemental analysis of dust trapped in air conditioner filters for the assessment of Lahore city's air quality

International Nuclear Information System (INIS)

Siddique, N.

2011-01-01

A study was undertaken to assess the air quality of Lahore by the elemental analysis of air conditioner (AC) filter dust samples collected from 15 different commercial sites. Samples were prepared using the Leeds Public Analyst Method and were analyzed using instrumental neutron activation analysis (INAA) for up to 31 elements. The elements Al, As, Ba, Ce, Co, Cr, Cs, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sc, Sm, Sn, Ta, Th, Yb and Zn were detected in all 15 samples whereas the remaining elements have been detected in fewer samples; i.e. Mg, Sb and Tb were detected in 14 samples, Br and V in ten samples, U in nine samples and Ca and Ti in eight samples only. Al, Ca, Fe, K, Mg and Na were determined in all samples at percentage levels. The concentrations of most elements were found to lie around the mean values for the 15 samples studied and were not orders of magnitude different. However the concentrations of Ca, Mg, Sn and Zn were found to be more variable and were found to be dependant on activities such as construction, fruit and vegetable handling, tin plating and transport, respectively. (author)

Life-cycle cost and payback period analysis for commercial unitary air conditioners

Energy Technology Data Exchange (ETDEWEB)

Rosenquist, Greg; Coughlin, Katie; Dale, Larry; McMahon, James; Meyers, Steve

2004-03-31

This report describes an analysis of the economic impacts of possible energy efficiency standards for commercial unitary air conditioners and heat pumps on individual customers in terms of two metrics: life-cycle cost (LCC) and payback period (PBP). For each of the two equipment classes considered, the 11.5 EER provides the largest mean LCC savings. The results show how the savings vary among customers facing different electricity prices and other conditions. At 11.5 EER, at least 80% of the users achieve a positive LCC savings. At 12.0 EER, the maximum efficiency analyzed, mean LCC savings are lower but still positive. For the {ge} $65,000 Btu/h to <135,000 Btu/h equipment class, 59% of users achieve a positive LCC savings. For the $135,000 Btu/h to <240,000 Btu/h equipment class, 91% of users achieve a positive LCC savings.

Experimental investigations on automobile air conditioners working with R134a and R290/R600a as an alternative

Directory of Open Access Journals (Sweden)

Kandhaswamy Karthikeyan

2017-01-01

Full Text Available In this work, the performance of R134a based automobile air conditioning system has been evaluated by retrofitted with R290/R600a mixture (in the ratio of 50:50, by mass, as an alternative. The performance was evaluated at five different operating speeds (1000, 1500, 2000, 2500, and 3000, which covers the entire range of working conditions with four different cabin load (100, 200, 300, and 400 W. The condenser inlet air temperature was varied in the range between 30 and 50°C, which covers the entire climatic variations in Coimbatore city of India. The performance characteristics such as, refrigerating effect, coefficient of performance, compressor power consumption, and compressor discharge temperatures were considered for comparison. The results showed that, hydrocarbon mixture has faster cooling rate due to its high latent heat of vaporization, 5% higher coefficient of performance due to higher refrigeration effect, 8-10 K lower compressor discharge temperature due to its lower specific heat ratio with 5% lower compressor power consumption due to its lower viscosity and lower liquid density. The charge requirement of R290/R600a mixture is about 50% less compared to R134a. However, the mixture composition is considered as an interment replacement in automobile air conditioners due to composition shift under leak-age conditions. Hence, R290/R600a mixture is considered as an interim energy efficient and environment friendly option in R134a automobile air conditioners to extend its life.

The use of heteroduplex analysis of polymerase chain reaction products to support the possible transmission of Legionella pneumophila from a malfunctioning automobile air conditioner.

Science.gov (United States)

Pinar, Ahmet; Ramirez, Julio A; Schindler, Laura L; Miller, Richard D; Summersgill, James T

2002-03-01

Air conditioner condensates have not been previously associated with cases of Legionnaires' disease. We report the possible transmission of Legionella pneumophila serogroup 1 from a malfunctioning automobile air conditioning system's leaking water onto the floorboard of a car driven for a long distance by the patient. Heteroduplex analysis of polymerase chain reaction products was used to help establish an epidemiologic link between the water specimen and the patient.

Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [ORNL; Munk, Jeffrey D [ORNL; Shrestha, Som S [ORNL; Linkous, Randall Lee [ORNL; Goetzler, William [Navigant Consulting Inc.; Guernsey, Matt [Navigant Consulting Inc.; Kassuga, Theo [Navigant Consulting Inc.

2015-08-01

The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Kassuga, Theo [Navigant Consulting Inc., Burlington, MA (United States)

2015-10-01

The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

Micromorphology of pelletized soil conditioners

Science.gov (United States)

Hirsch, Florian; Dietrich, Nils; Knoop, Christine; Raab, Thomas

2017-04-01

Soil conditioners produced by anaerobic digestion and subsequent composting of organic household waste, bear the potential to improve unproductive farmland together with a reduced input risk of unwanted pollutants into the soils. Within the VeNGA project (http://www.biogas-network.de/venga), soil conditioners from anaerobically digested organic household waste are tested for their potential to increase plant growth in glasshouse and field experiments. Because the production techniques of these soil conditioners may influence their physical and chemical behaviour in the soil, two different techniques for pelletizing the soil conditioners where applied. We present findings from a pot experiment with cereal that has been sampled after two months for micromorphological analyses. We visualize the decomposition and the physical behaviour of the soil conditioners. Pellets produced in an agglomeration mixer result in dense balls, that are only slightly decomposed after the trial. But the soil conditioners created under pressure in a screw extruder are rich in voids and have the potential of retaining more soil water.

Thermal comfort and indoor air quality in the lecture room with 4-way cassette air-conditioner and mixing ventilation system

International Nuclear Information System (INIS)

Noh, Kwang-Chul; Jang, Jae-Soo; Oh, Myung-Do

2007-01-01

We performed the experimental and the numerical studies on thermal comfort (TC) and indoor air quality (IAQ) in the lecture room with cooling loads when the operating conditions are changed. Predicted mean vote (PMV) value and CO 2 concentration of the lecture room were measured and compared to the numerical results. Both of them showed a reasonable agreement with each other and then we applied the numerical model to analyze TC and IAQ for a couple of different operating conditions. From the results we found that the increment of the discharge angle of 4-way cassette air-conditioner makes uniformity of TC worse, but rarely affects IAQ. It turned out that TC and IAQ are hardly affected by the variation of the discharge airflow. Finally TC was merely affected by the increment of the ventilation rate, but when the ventilation rate is more than 800m 3 /h, the average CO 2 concentration can be satisfied with the standard limits of Japanese in our case studies. (author)

Investigation on a two-stage solar liquid-desiccant (LiBr) dehumidification system assisted by CaCl2 solution

International Nuclear Information System (INIS)

Xiong, Z.Q.; Dai, Y.J.; Wang, R.Z.

2009-01-01

A two-stage solar powered liquid-desiccant dehumidification system, for which two kinds of desiccant solution (lithium chloride and calcium bromide) are fed to the two dehumidification stages separately, has been studied. In the studied system air moisture (latent) load is separately removed by a pre-dehumidifier using cheap calcium chloride (CaCl 2 ) and a main dehumidifier using stable lithium bromide (LiBr). Side-effect of mixing heat rejected during dehumidification process is considerably alleviated by an indirect evaporative cooling unit added between the two dehumidification stages. The feasibility of high-desiccant concentration difference achieved by reusing desiccant solution to dehumidify air and regenerating desiccant repeatedly is analyzed. By increasing desiccant concentration difference, desiccant storage capacity is effectively explored. It is found that the pre-dehumidification effect of CaCl 2 solution is significant in high ambient humidity condition. Also seen is that the desiccant investment can be decreased by 53%, though the cost of equipments is somewhat increased, and the Tcop and COP of the proposed system can reach 0.97 and 2.13, respectively

10 CFR Appendix M to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Central Air Conditioners and Heat Pumps

Science.gov (United States)

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Uniform Test Method for Measuring the Energy Consumption... Consumption of Central Air Conditioners and Heat Pumps 1. DEFINITIONS 2. TESTING CONDITIONS 2.1Test room... more common ducts within each test room that contains multiple indoor coils. At the plane where each...

Experimental investigation of HFC407C/HC290/HC600a mixture in a window air conditioner

International Nuclear Information System (INIS)

Jabaraj, D.B.; Avinash, P.; Lal, D. Mohan; Renganarayan, S.

2006-01-01

HCFC22, one of the widely used refrigerants in window air conditioners must be phased out soon as per the Montreal protocol. Presently, HFC407C is considered as a potential drop in substitute for HCFC22, but retrofitting HCFC22 systems with HFC407C with polyol ester oil (POE) is a major issue as HFC407C is immiscible with mineral oil. The miscibility issue of HFC407C with mineral oil was overcome with the addition of a HC blend to it. The above technoeconomic feasibility issues to retrofit the existing HCFC22 systems with an ozone friendly refrigerant and retain the energy efficiency of the system are challenges in the air conditioning sector. In this present work, an experimental analysis has been conducted in a window air conditioner retrofitted with eco-friendly refrigerant mixtures of HFC407C/HC290/HC600a without changing the mineral oil. Its performance, as well as energy consumption, was compared with the conventional one. It is observed that the mixtures demand lengthening of the condenser in order to maintain the discharge pressure within acceptable limits. This also resulted in better heat transfer at the condenser. Therefore, in this study, the condenser tube length was increased by 19% to suit the mixtures as compared to HCFC22. Compared to HCFC22, the refrigeration capacity of the new mixture was 9.54-12.76% higher than that of HCFC22, while the actual COP was found to be 11.91-13.24% higher than that of HCFC22. The overall performance has proved that the HFC407C/HC blend refrigerant mixture could be an eco-friendly substitute to phase out HCFC22

Transcriptomic analysis of Salmonella desiccation resistance.

Science.gov (United States)

Li, Haiping; Bhaskara, Anuhya; Megalis, Christina; Tortorello, Mary Lou

2012-12-01

The survival of Salmonella in low moisture foods and processing environments remains a great challenge for the food industry and public health. To explore the mechanisms of Salmonella desiccation resistance, we studied the transcriptomic responses in Salmonella Tennessee (Tennessee), using Salmonella Typhimurium LT2 (LT2), a strain weakly resistant to desiccation, as a reference strain. In response to 2 h of air-drying at 11% equilibrated relative humidity, approximately one-fourth of the open reading frames (ORFs) in the Tennessee genome and one-fifth in LT2 were differentially expressed (>2-fold). Among all differentially expressed functional groups (>5-fold) in both strains, the expression fold change associated with fatty acid metabolism was the highest, and constituted 51% and 35% of the total expression fold change in Tennessee and LT2, respectively. Tennessee showed greater changes in expression of genes associated with stress response and envelope modification than LT2, while showing lesser changes in protein biosynthesis expression. Expression of flagella genes was significantly more inhibited in stationary phase cells of Tennessee than LT2 both before and after desiccation. The accumulation of the osmolyte trehalose was significantly induced by desiccation in Tennessee, but no increase was detectable in LT2, which is consistent with the expression patterns of the entire trehalose biosynthesis and degradation pathways in both strains. Results from this study present a global view of the dynamic desiccation responses in Salmonella, which will guide future research efforts to control Salmonella in low moisture environments.

Draft Genome Sequence of a Novel Chitinophaga sp. Strain, MD30, Isolated from a Biofilm in an Air Conditioner Condensate Pipe.

Science.gov (United States)

Wan, Xuehua; Darris, Maxwell; Hou, Shaobin; Donachie, Stuart P

2017-10-19

Most of the 24 known Chitinophaga species were originally isolated from soils. We report the draft genome sequence of a putatively novel Chitinophaga sp. from a biofilm in an air conditioner condensate pipe. The genome comprises 7,661,303 bp in one scaffold, 5,694 predicted protein-coding sequences, and a G+C content of 47.6%. Copyright © 2017 Wan et al.

Effect of heat recovery water heater system on the performance of residential split air conditioner using hydrocarbon refrigerant (HCR22)

Science.gov (United States)

Aziz, A.; Thalal; Amri, I.; Herisiswanto; Mainil, A. K.

2017-09-01

This This paper presents the performance of residential split air conditioner (RSAC) using hydrocarbon refrigerant (HCR22) as the effect on the use of heat recovery water heater system (HRWHS). In this study, RSAC was modified with addition of dummy condenser (trombone coil type) as heat recovery water heater system (HRWHS). This HRWHS is installed between a compressor and a condenser by absorbing a part of condenser waste heat. The results show that RSAC with HRWHS is adequate to generate hot water with the temperature range about 46.58˚C - 48.81˚C when compared to without HRWHS and the use of dummy condenser does not give significant effect to the split air conditioner performance. When the use of HRWHS, the refrigerant charge has increase about 19.05%, the compressor power consumption has slightly increase about 1.42% where cooling capacity almost the same with slightly different about 0.39%. The condenser heat rejection is lower about 2.68% and the COP has slightly increased about 1.05% when compared to without HRWHS. The use of HRWHS provide free hot water, it means there is energy saving for heating water without negative impact to the system performance of RSAC.

Primary energy savings in desiccant and evaporative cooling-assisted 100% outdoor air system combined with a fuel cell

International Nuclear Information System (INIS)

Kim, Min-Hwi; Dong, Hae-Won; Park, Joon-Young; Jeong, Jae-Weon

2016-01-01

Highlights: • A LD-IDECOAS integrated with a PEMFC was proposed. • A pilot system was installed and tested during cooling operation. • The proposed system powered by the PEMFC saved 21% of the primary energy consumption during cooling. - Abstract: The main purpose of this study involved investigating the primary energy saving potential of a liquid desiccant and evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS) integrated with a proton exchange membrane fuel cell (PEMFC). During the cooling season, the heat produced by the PEMFC was used to regenerate a weak desiccant solution, and the electricity generated was used to operate the LD-IDECOAS. A pilot LD-IDECOAS powered by a PEMFC was installed and operated in an office space to experimentally verify the annual operating energy savings of the proposed system. The findings indicated that the heat reclaimed from the PEMFC saved 42% of the desiccant solution regenerating energy when compared to that in the case of a conventional gas-fired water heater. The results also suggested that the LD-IDECOAS combined with a PEMFC consumed 21% less primary energy when compared with that of a system powered by grid electricity and a conventional gas-fired water heater.

Thermodynamic analysis of a novel energy-efficient refrigeration system subcooled by liquid desiccant dehumidification and evaporation

International Nuclear Information System (INIS)

She, Xiaohui; Yin, Yonggao; Zhang, Xiaosong

2014-01-01

Highlights: • An energy-efficient refrigeration system with a novel subcooling method is proposed. • Thermodynamic analysis is conducted to discuss the effects of operation parameters. • Two different utilization ways of condensation heat are compared. • The system achieves much higher COP, even higher than reverse Carnot cycle. • Suggested mass concentration for LiCl–H 2 O is around 32% at a typical case. - Abstract: A new energy-efficient refrigeration system subcooled by liquid desiccant dehumidification and evaporation was proposed in this paper. In the system, liquid desiccant system could produce very dry air for an indirect evaporative cooler, which would subcool the vapor compression refrigeration system to get higher COP than conventional refrigeration system. The desiccant cooling system can use the condensation heat for the desiccant regeneration. Thermodynamic analysis is made to discuss the effects of operation parameters (condensing temperature, liquid desiccant concentration, ambient air temperature and relative humidity) on the system performance. Results show that the proposed hybrid vapor compression refrigeration system achieves significantly higher COP than conventional vapor compression refrigeration system, and even higher than the reverse Carnot cycle at the same operation conditions. The maximum COPs of the hybrid systems using hot air and ambient air are 18.8% and 16.3% higher than that of the conventional vapor compression refrigeration system under varied conditions, respectively

Energy performance of solar-assisted liquid desiccant air-conditioning system for commercial building in main climate zones

International Nuclear Information System (INIS)

Qi, Ronghui; Lu, Lin; Huang, Yu

2014-01-01

Highlights: • Simulation of solar liquid desiccant AC system in four climate regions was conducted. • System performance was determined by relationship of sensible and latent cooling load. • For humid area, saving amount is large by handling latent load with solar energy. • For dry area, electricity saving rate is considerable due to the high COP of chillers. • For buildings with mild SHR, the system performance was not as good as others. - Abstract: Liquid desiccant air-conditioning (LDAC) system, which consists of a liquid desiccant ventilation system for dehumidification and an air-handling unit for cooling, has become a promising alternative for conventional technology. To evaluate its feasibility and applicability, the simulation of solar-assisted LDAC (SLDAC) in commercial buildings in five cities of four main climate regions were conducted, including Singapore in Tropical, Houston and Beijing in Temperate, Boulder in Arid and Los Angeles in Mediterranean. Results showed that the system’s performance was seriously affected by the ratios of building’s sensible and latent cooling load. For buildings located in humid areas with low sensible-total heat ratio (SHR), the electricity energy reduction of SLDAC was high, about 450 MW h in Houston and Singapore, which accounted for 40% of the total energy consumption in cooling seasons. The cost payback period was as short as approximately 7 years. The main reason is that the energy required for handling the moisture could be saved by liquid desiccant dehumidification, and the regeneration heat could be covered by solar collectors. For buildings in dry climate with high SHR, the total cooling load was low, but up to 45% electricity of AC system could be saved in Boulder because the chiller COP could be significantly improved during more than 70% operation time. The cost payback period was around 22 years, which was acceptable. However, for the buildings with mild SHR, such as those in Beijing and Los

Desiccant-Based Preconditioning Market Analysis

Energy Technology Data Exchange (ETDEWEB)

Fischer, J.

2001-01-11

A number of important conclusions can be drawn as a result of this broad, first-phase market evaluation. The more important conclusions include the following: (1) A very significant market opportunity will exist for specialized outdoor air-handling units (SOAHUs) as more construction and renovation projects are designed to incorporate the recommendations made by the ASHRAE 62-1989 standard. Based on this investigation, the total potential market is currently $725,000,000 annually (see Table 6, Sect. 3). Based on the market evaluations completed, it is estimated that approximately $398,000,000 (55%) of this total market could be served by DBC systems if they were made cost-effective through mass production. Approximately $306,000,000 (42%) of the total can be served by a non-regenerated, desiccant-based total recovery approach, based on the information provided by this investigation. Approximately $92,000,000 (13%) can be served by a regenerated desiccant-based cooling approach (see Table 7, Sect. 3). (2) A projection of the market selling price of various desiccant-based SOAHU systems was prepared using prices provided by Trane for central-station, air-handling modules currently manufactured. The wheel-component pricing was added to these components by SEMCO. This resulted in projected pricing for these systems that is significantly less than that currently offered by custom suppliers (see Table 4, Sect. 2). Estimated payback periods for all SOAHU approaches were quite short when compared with conventional over-cooling and reheat systems. Actual paybacks may vary significantly depending on site-specific considerations. (3) In comparing cost vs benefit of each SOAHU approach, it is critical that the total system design be evaluated. For example, the cost premium of a DBC system is very significant when compared to a conventional air handling system, yet the reduced chiller, boiler, cooling tower, and other expense often equals or exceeds this premium, resulting in a

Assessment of Energy, Environmental and Economic Performance of a Solar Desiccant Cooling System with Different Collector Types

Directory of Open Access Journals (Sweden)

Giovanni Angrisani

2014-10-01

Full Text Available Desiccant-based air handling units can achieve reductions in greenhouse gas emissions and energy savings with respect to conventional air conditioning systems. Benefits are maximized when they interact with renewable energy technologies, such as solar collectors. In this work, experimental tests and data derived from scientific and technical literature are used to implement a model of a solar desiccant cooling system, considering three different collector technologies (air, flat-plate and evacuated collectors. Simulations were then performed to compare the energy, environmental and economic performance of the system with those of a desiccant-based unit where regeneration thermal energy is supplied by a natural gas boiler, and with those of a conventional air-handling unit. The only solution that allows achieving the economic feasibility of the solar desiccant cooling unit consists of 16 m2 of evacuated solar collectors. This is able to obtain, with respect to the reference system, a reduction of primary energy consumption and of the equivalent CO2 emissions of 50.2% and 49.8%, respectively, but with a payback time of 20 years.

Locating room air-conditioners at floor level for energy saving in residential buildings

Energy Technology Data Exchange (ETDEWEB)

Gao, C.F.; Lee, Hua; Chen, W.L. [Department of Building Services Engineering, Hong Kong Polytechnic University, Hung Hom (China)

2009-08-15

Residential air-conditioning becomes a common feature in our daily life. They are typically installed at high level known as ceiling-based system (CAC). With the increasing use of floor-based air-conditioning system in commercial buildings for energy saving, it is proposed in this study to locate a top discharge/front return air-conditioner at floor level to resemble a floor-based air-conditioning system (FAC) to curb energy use in residential buildings. Given the concerns about draught discomfort and thermal stratification associated with floor-based air-conditioning systems, the objective of this study is to evaluate the air distribution performance and to quantify the possible energy benefits. Bedroom was chosen as a sensitive case for detailed air distribution performance evaluation. Experimental study, CFD simulations and energy simulations were conducted in achieving the specific objectives. CAC and FAC were installed in a bedroom-like environmental chamber for experimental study at different indoor and outdoor conditions. The air velocities and temperatures at various positions and levels inside the chamber were measured to determine the air distribution performance indices (ADPI) and airflow draft risk (DR). The cooling output, power consumption and coefficient of performance (COP) of the two units were measured and calculated for comparison. The experimental results show that ADPI of CAC and FAC are 92.3% and 84.6%, respectively. COP of FAC is 8.11% higher than CAC, and the corresponding DR are comparable. The experimental results were used to validate the CFD simulations as well as providing actual performance data for predicting the energy use of applying CAC and FAC in a case-study building. CFD simulations and draught assessment confirmed that there is no potential draught discomfort and thermal stratification associated with the use of FAC. Energy simulations predicted that the associated energy saving is 6.9%. Wider use of FAC in residential

Clay with Desiccation Cracks is an Advection Dominated Environment

Science.gov (United States)

Baram, S.; Kurtzman, D.; Sher, Y.; Ronen, Z.; Dahan, O.

2012-04-01

, indicating deep soil evaporation. Daily fluctuation of the air temperature in the desiccation cracks supported thermally induced air convection within the cracks void and could explain the deep soil salinization process. Combination of all the abovementioned observations demonstrated that the formation of desiccation cracks network in dispersive clay sediments generates a bulk advection dominated environment for both air and water flow, and that the reference to clay sediments as "hydrologically safe" should to be reconsidered.

Ventilation influence upon indoor air radon level

International Nuclear Information System (INIS)

Tian Deyuan

1995-01-01

Levels of indoor radon in air are studied by a continuous electrostatic radon monitor under normal living conditions to evaluate the influence of air conditioned ventilation on indoor air radon level. Results show that the indoor air radon concentrations are not much more than those without household conditioner living condition, although using household conditioner requires a sealed room which should lead to a higher radon level. Turning on air conditioner helps lower indoor radon level. Therefore, the total indoor air Rn levels are normal > ventilation > exhaust or in-draft > exhaust plus in-draft

Greenhouse gas emissions for refrigerant choices in room air conditioner units.

Science.gov (United States)

Galka, Michael D; Lownsbury, James M; Blowers, Paul

2012-12-04

In this work, potential replacement refrigerants for window-mounted room air conditioners (RACs) in the U.S. have been evaluated using a greenhouse gas (GHG) emissions analysis. CO(2)-equivalent emissions for several hydrofluoroethers (HFEs) and other potential replacements were compared to the most widely used refrigerants today. Included in this comparison are pure refrigerants that make up a number of hydrofluorocarbon (HFC) mixtures, pure hydrocarbons, and historically used refrigerants such as propane and ammonia. GHG emissions from direct and indirect sources were considered in this thermodynamic analysis. Propylene, dimethyl ether, ammonia, R-152a, propane, and HFE-152a all performed effectively in a 1 ton window unit and produced slightly lower emissions than the currently used R-22 and R-134a. The results suggest that regulation of HFCs in this application would have some effect on reducing emissions since end-of-life emissions remain at 55% of total refrigerant charge despite EPA regulations that mandate 80% recovery. Even so, offsite emissions due to energy generation dominate over direct GHG emissions and all the refrigerants perform similarly in totals of indirect GHG emissions.

Determination of heavy metals in air conditioner dust using FAAS and INAA

International Nuclear Information System (INIS)

Siddique, N.

2012-01-01

The elements Cd, Cr, Cu, Mn, Ni, Pb and Zn were determined in dust samples collected from air conditioner (AC) filters from 15 commercial sites of Lahore using flame atomic absorption spectroscopy (FAAS). The elements Cr, Mn and Zn were also determined using instrumental neutron activation analysis (INAA). The results obtained showed that higher amounts of these metals were measured in these dust samples than normally found in soil. This was especially true for Cd, Cu, Pb and Zn. Generally the amounts of Cd, Cr and Mn did not vary throughout the city of Lahore but the amounts of the traffic related Cu, Pb and Zn elements had the more variable ranges of 30-140, 30-230 and 74-2810 mg/kg respectively. The concentrations obtained for Cr, Mn and Zn by INAA were found to be higher than those obtained using FAAS. Analysis of the data obtained showed the digestion procedure employed to be the possible cause for this occurrence. It was also found that Mn was being over-estimated by INAA due to the interference from the Mg peak. (author)

Bifurcated SEN with Fluid Flow Conditioners

Directory of Open Access Journals (Sweden)

F. Rivera-Perez

2014-01-01

Full Text Available This work evaluates the performance of a novel design for a bifurcated submerged entry nozzle (SEN used for the continuous casting of steel slabs. The proposed design incorporates fluid flow conditioners attached on SEN external wall. The fluid flow conditioners impose a pseudosymmetric pattern in the upper zone of the mold by inhibiting the fluid exchange between the zones created by conditioners. The performance of the SEN with fluid flow conditioners is analyzed through numerical simulations using the CFD technique. Numerical results were validated by means of physical simulations conducted on a scaled cold water model. Numerical and physical simulations confirmed that the performance of the proposed SEN is superior to a traditional one. Fluid flow conditioners reduce the liquid free surface fluctuations and minimize the occurrence of vortexes at the free surface.

Using Field-Metered Data to Quantify Annual Energy Use of Portable Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Burke, Thomas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Ni, Chun Chun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Stratton, Hannah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Chen, Yuting [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Ganeshalingam, Mohan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Iyer, Maithili [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Price, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division; Dunham, Camilla [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Dept., Environmental Energy Technologies Division

2014-12-12

As many regions of the United States experience rising temperatures, consumers have come to rely increasingly on cooling appliances (including portable air conditioners) to provide a comfortable indoor temperature. Home occupants sometimes use a portable air conditioner (PAC) to maintain a desired indoor temperature in a single room or enclosed space. Although PACs in residential use are few compared to centrally installed and room air conditioning (AC) units, the past few years have witnessed an increase of PACs use throughout the United States. There is, however, little information and few research projects focused on the energy consumption and performance of PACs, particularly studies that collect information from field applications of PACs. The operation and energy consumption of PACs may differ among geographic locations and households, because of variations in cooling load, frequency, duration of use, and other user-selected settings. In addition, the performance of building envelope (thermal mass and air leakage) as well as inter-zonal mixing within the building would substantially influence the ability to control and maintain desirable indoor thermal conditions. Lawrence Berkeley National Laboratory (LBNL) conducted an initial field-metering study aimed at increasing the knowledge and data related to PAC operation and energy consumption in the United States. LBNL performed its field-metering study from mid-April to late October 2014. The study, which monitored 19 sites in the Northeastern United States (4 in upstate New York and 15 near Philadelphia), collected real-time data on PAC energy consumption along with information regarding housing characteristics, consumer behavior, and environmental conditions that were expected to affect PAC performance. Given the limited number of test sites, this study was not intended to be statistically representative of PAC users in the United States but rather to understand the system response to the cooling demand and to

Space shuttle aps propellant thermal conditioner study

Science.gov (United States)

Fulton, D. L.

1973-01-01

An analytical and experimental effort was completed to evaluate a baffle type thermal conditioner for superheating O2 and H2 at supercritical pressures. The thermal conditioner consisted of a heat exchanger and an integral reactor (gas generator) operating on O2/H2 propellants. Primary emphasis was placed on the hydrogen conditioner with some effort on the oxygen conditioner and a study completed of alternate concepts for use in conditioning oxygen. A hydrogen conditioner was hot fire tested under a range of conditions to establish ignition, heat exchange and response parameters. A parallel technology task was completed to further evaluate the integral reactor and heat exchanger with the side mounted electrical spark igniter.

Proposal of digital interface for the system of the air conditioner's remote control: analysis of the system of feedback.

Science.gov (United States)

da Silva de Queiroz Pierre, Raisa; Kawada, Tarô Arthur Tavares; Fontes, André Guimarães

2012-01-01

Develop a proposal of digital interface for the system of the remote control, that functions as support system during the manipulation of air conditioner adjusted for the users in general, from ergonomic parameters, objectifying the reduction of the problems faced for the user and improving the process. 20 people with questionnaire with both qualitative and quantitative level. Linear Method consists of a sequence of steps in which the input of one of them depends on the output from the previous one, although they are independent. The process of feedback, when necessary, must occur within each step separately.

Shuttle APS propellant thermal conditioner study

Science.gov (United States)

Pearson, W. E.

1971-01-01

A study program was performed to allow selection of thermal conditioner assemblies for superheating O2 and H2 at supercritical pressures. The application was the auxiliary propulsion system (APS) for the space shuttle vehicle. The O2/H2 APS propellant feed system included propellant conditioners, of which the thermal conditioner assemblies were a part. Cryogens, pumped to pressures above critical, were directed to the thermal conditioner assembly included: (1) a gas generator assembly with ignition system and bipropellant valves, which burned superheated O2 and H2 at rich conditions; (2) a heat exchanger assembly for thermal conditioning of the cryogenic propellant; and (3) a dump nozzle for heat exchanger exhaust.

Thermodynamic analysis of an open cycle solid desiccant cooling system using Artificial Neural Network

International Nuclear Information System (INIS)

Koronaki, I.P.; Rogdakis, E.; Kakatsiou, T.

2012-01-01

Highlights: ► A neural network model based on experimental data was developed. ► Description of the experimental setup. ► Prediction of the state conditions of air at the process and regeneration stream. ► Sensitivity Analysis performed on these predicted results. ► Predicted output values in line with correlation model based on data from industry. - Abstract: This paper examines the performance of an installed open cycle air-conditioning system with a silica gel desiccant wheel which uses a conventional heat pump and heat exchangers for the improvement of the outlet air of the system. A neural network model based on the training of a black box model with experimental data was developed as a method based on experimental results predicting the state conditions of air at the process and regeneration stream. The model development was followed by a Sensitivity Analysis performed on these predicted results. The key parameters were the thermodynamic condition of process and regeneration air streams, the sensible heat factor of the room, and the mass air flow ratio of the regeneration and process streams. The results of this analysis revealed that all investigated parameters influenced the performance of the desiccant unit. Predicted output values of the proposed Neural Network Model for Desiccant Systems are in line with results from other correlation models based on the interpolation of experimental data obtained from industrial air conditioning installations.

Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

Energy Technology Data Exchange (ETDEWEB)

Kim, Chul Jin; Choi, Hyo Hyun [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Sohn, Chae Hoon, E-mail: chsohn@sejong.ac.kr [Department of Mechanical Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)

2011-01-15

Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner

International Nuclear Information System (INIS)

Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

2011-01-01

Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 deg. C. First, its auto-ignition temperature is measured 365 deg. C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 deg. C to 255 deg. C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

Performance investigation on the ultrasonic atomization liquid desiccant regeneration system

International Nuclear Information System (INIS)

Yang, Zili; Zhang, Kaisheng; Hwang, Yunho; Lian, Zhiwei

2016-01-01

Highlights: • We applied ultrasonic atomization technology to boost liquid desiccant regeneration. • We established a novel UARS and made a thorough study on its performance. • We developed a performance prediction model for UARS and validated its accuracy. • The necessary regeneration temperature dropped significantly (4.4 °C) in UARS. • Energy consumption for regenerating desiccant was reduced greatly (60.4%) in UARS. - Abstract: Liquid desiccant dehumidification systems have accumulated considerable research interest in recent years for their great energy saving potential in buildings. Within the system, the regenerator recovering liquid desiccant plays a major role in its performance. When the ultrasonic atomization technology is applied to atomize the desiccant solution into numerous tiny droplets with diameters around 50 μm, the regeneration process could be greatly enhanced. To validate this approach, a novel ultrasonic atomization liquid desiccant regeneration system (UARS) was studied in this work. An Ideal Regeneration Model (IRM) was developed to predict the regeneration performance of the UARS. Additionally, thorough experiments were carried out to validate the model under different operating conditions of the desiccant solution and air stream. The model predicted values and the experimental results coincided, with the average deviation less than 7.9%. The performance of UARS was compared with other regeneration systems from the open literature, while a case study was conducted for the power consumption and energy saving potential of UARS. It was found that the ultrasonic atomization technology enabled utilization of lower-grade energy for desiccant regeneration with the regeneration temperature lowered as much as 4.4 °C. In addition, a considerable energy saving potential of up to 23.4% could be achieved by the UARS for regenerating per unit mass flow of desiccant solution, while the power consumption of the ultrasonic atomization system

Effect of irreversible processes on the thermodynamic performance of open-cycle desiccant cooling cycles

International Nuclear Information System (INIS)

La, Dong; Li, Yong; Dai, Yanjun; Ge, Tianshu; Wang, Ruzhu

2013-01-01

Highlights: ► Effects of irreversible processes on the performance of desiccant cooling cycle are identified. ► The exergy destructions involved are classified by the properties of the individual processes. ► Appropriate indexes for thermodynamic evaluation are proposed based on thermodynamic analyses. - Abstract: Thermodynamic analyses of desiccant cooling cycle usually focus on the overall cycle performance in previous study. In this paper, the effects of the individual irreversible processes in each component on thermodynamic performance are analyzed in detail. The objective of this paper is to reveal the elemental features of the individual components, and to show their effects on the thermodynamic performance of the whole cycle in a fundamental way. Appropriate indexes for thermodynamic evaluation are derived based on the first and second law analyses. A generalized model independent of the connection of components is developed. The results indicate that as the effectiveness of the desiccant wheel increases, the cycle performance is increased principally due to the significant reduction in exergy carried out by exhaust air. The corresponding exergy destruction coefficient of the cycle with moderate performance desiccant wheel is decreased greatly to 3.9%, which is more than 50% lower than that of the cycle with low performance desiccant wheel. The effect of the heat source is similar. As the temperature of the heat source increases from 60 °C to 90 °C, the percentage of exergy destruction raised by exhaust air increases sharply from 5.3% to 21.8%. High heat exchanger effectiveness improves the cycle performance mainly by lowering the irreversibility of the heat exchanger, using less regeneration heat and pre-cooling the process air effectively

Moving Advanced Desiccant Materials into Mainstream Non-CFC Cooling Products

Energy Technology Data Exchange (ETDEWEB)

Sand, J. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grossman, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fairchild, P. D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gross, I. L. [Engelhard/ICC, Hatboro, PA (United States). Fresh Air Solutions

2004-12-30

Desiccant dehumidification technology is emerging as a technically viable alternative for comfort conditioning in many commercial and institutional buildings. Attempts to improve the indoor air quality of buildings has resulted in increasingly stringent guidelines for occupant outdoor air ventilation rates. Additionally, revised building heating, ventilating, and air-conditioning (HVAC) design criteria based on regional peak dew point data highlight the important of the latent (moisture removal) building load relative to the sensible (temperature) building load.

A heat pump driven and hollow fiber membrane-based liquid desiccant air dehumidification system: Modeling and experimental validation

International Nuclear Information System (INIS)

Zhang, Li-Zhi; Zhang, Ning

2014-01-01

A compression heat pump driven and membrane-based liquid desiccant air dehumidification system is presented. The dehumidifier and the regenerator are made of two hollow fiber membrane bundles packed in two shells. Water vapor can permeate through these membranes effectively, while the liquid desiccant droplets are prevented from cross-over. Simultaneous heating and cooling of the salt solution are realized with a heat pump system to improve energy efficiency. In this research, the system is built up and a complete modeling is performed for the system. Heat and mass transfer processes in the membrane modules, as well as in the evaporator, the condenser, and other key components are modeled in detail. The whole model is validated by experiment. The performances of SDP (specific dehumidification power), dehumidification efficiency, EER (energy efficiency ratio) of heat pump, and the COP (coefficient of performance) of the system are investigated numerically and experimentally. The results show that the model can predict the system accurately. The dehumidification capabilities and the energy efficiencies of the system are high. Further, it performs well even under the harsh hot and humid South China weather conditions. - Highlights: • A membrane-based and heat pump driven air dehumidification system is proposed. • A real experimental set up is built and used to validate the model for the whole system. • Performance under design and varying operation conditions is investigated. • The system performs well even under harsh hot and humid conditions

Desiccation-crack-induced salinization in deep clay sediment

Directory of Open Access Journals (Sweden)

S. Baram

2013-04-01

Full Text Available A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water content and on the chemical and isotopic composition of the sediment and pore water in it. The isotopic composition of water stable isotopes (δ18O and δ2H in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ~ 3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl− concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a desiccation-crack-induced salinization (DCIS conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

Smart Sensors Enable Smart Air Conditioning Control

Directory of Open Access Journals (Sweden)

Chin-Chi Cheng

2014-06-01

Full Text Available In this study, mobile phones, wearable devices, temperature and human motion detectors are integrated as smart sensors for enabling smart air conditioning control. Smart sensors obtain feedback, especially occupants’ information, from mobile phones and wearable devices placed on human body. The information can be used to adjust air conditioners in advance according to humans’ intentions, in so-called intention causing control. Experimental results show that the indoor temperature can be controlled accurately with errors of less than ±0.1 °C. Rapid cool down can be achieved within 2 min to the optimized indoor capacity after occupants enter a room. It’s also noted that within two-hour operation the total compressor output of the smart air conditioner is 48.4% less than that of the one using On-Off control. The smart air conditioner with wearable devices could detect the human temperature and activity during sleep to determine the sleeping state and adjusting the sleeping function flexibly. The sleeping function optimized by the smart air conditioner with wearable devices could reduce the energy consumption up to 46.9% and keep the human health. The presented smart air conditioner could provide a comfortable environment and achieve the goals of energy conservation and environmental protection.

Conditioner for a helically transported electron beam

International Nuclear Information System (INIS)

Wang, Changbiao.

1992-05-01

The kinetic theory is developed to investigate a conditioner for a helically transported electron beam. Linear expressions for axial velocity spread are derived. Numerical simulation is used to check the theoretical results and examine nonlinear aspects of the conditioning process. The results show that in the linear regime the action of the beam conditioner on a pulsed beam mainly depends on the phase at which the beam enters the conditioner and depends only slightly on the operating wavelength. In the nonlinear regime, however, the action of the conditioner strongly depends on the operating wavelength and only slightly upon the entrance phase. For a properly chosen operating wavelength, a little less than the electron's relativistic cyclotron wavelength, the conditioner can decrease the axial velocity spread of a pulsed beam down to less than one-third of its initial value

Conditioner for a helically transported electron beam

International Nuclear Information System (INIS)

Wang, C.

1992-05-01

The kinetic theory is developed to investigate a conditioner for a helically imported electron beam. Linear expressions for axial velocity spread are derived. Numerical simulation is used to check the theoretical results and examine nonlinear aspects of the conditioning process. The results show that in the linear regime the action of the beam conditioner on a pulsed beam mainly depends on the phase at which the beam enters the conditioner and depends only slightly on the operating wavelength. In the nonlinear regime, however, the action of the conditioner strongly depends on the operating wavelength and only slightly upon the entrance phase. For a properly chosen operating wavelength, a little less than the electron's relativistic cyclotron wavelength, the conditioner can decrease the axial velocity spread of a pulsed beam down to less than one-third of its initial value

Semi-empiric model of an air cooled cabinet air conditioner for the dynamic analysis of the building and acclimation systems integrated behaviour; Modelo semi-empirico de condicionador de gabinete resfriado a ar para analise dinamica do comportamento integrado de edificacoes e sistemas de climatizacao

Energy Technology Data Exchange (ETDEWEB)

Correa, Jorge E. [Para Univ., Belem (Brazil). Dept. de Engenharia Mecanica]. E-mail: jecorrea@amazon.com.br; Melo, Claudio. E-mail: melo@nrva.ufsc.br; Negrao, Cezar O. R. E-mail: negrao@energia.damec.cefetpr.br

2000-07-01

This work presents a semi-empirical model for a air cooled case air conditioner. This model is to be inserted in the EPS-r program (Environmental System Performance - research version) allowing the dynamic analysis of the integrated behaviour of buildings and acclimation systems using this equipment. Results obtained from simulations under the operation conditions existing in Brazil are analysed.

Desiccant cooling: State-of-the-art assessment

Energy Technology Data Exchange (ETDEWEB)

Pesaran, A.A.; Penney, T.R.; Czanderna, A.W.

1992-10-01

The objectives of this document are to present an overview of the work accomplished to date on desiccant cooling to provide assessment of the state of the art of desiccant cooling technology in the field of desiccant material dehumidifier components, desiccant systems, and models. The report also discusses the factors that affect the widespread acceptance of desiccant cooling technology. This report is organized as follows. First, a basic description and historical overview of desiccant cooling technology is provided. Then, the recent research and development (R D) program history (focusing on DOE's funded efforts) is discussed. The status of the technology elements (materials, components, systems) is discussed in detail and a preliminary study on the energy impact of desiccant technology is presented. R D needs for advancing the technology in the market are identified. The National Renewable Energy Laboratory's unique desiccant test facilities and their typical outputs are described briefly. Finally, the results of a comprehensive literature search on desiccant cooling are presented in a bibliography. The bibliography contains approximately 900 citations on desiccant cooling.

Desiccant cooling: State-of-the-art assessment

Energy Technology Data Exchange (ETDEWEB)

Pesaran, A.A.; Penney, T.R.; Czanderna, A.W.

1992-10-01

The objectives of this document are to present an overview of the work accomplished to date on desiccant cooling to provide assessment of the state of the art of desiccant cooling technology in the field of desiccant material dehumidifier components, desiccant systems, and models. The report also discusses the factors that affect the widespread acceptance of desiccant cooling technology. This report is organized as follows. First, a basic description and historical overview of desiccant cooling technology is provided. Then, the recent research and development (R&D) program history (focusing on DOE`s funded efforts) is discussed. The status of the technology elements (materials, components, systems) is discussed in detail and a preliminary study on the energy impact of desiccant technology is presented. R&D needs for advancing the technology in the market are identified. The National Renewable Energy Laboratory`s unique desiccant test facilities and their typical outputs are described briefly. Finally, the results of a comprehensive literature search on desiccant cooling are presented in a bibliography. The bibliography contains approximately 900 citations on desiccant cooling.

78 FR 37220 - Proposed Information Collection Request; Comment Request; EPA-ICR No. 1774.05-Mobile Air...

Science.gov (United States)

2013-06-20

.... Regulations promulgated under SNAP require that Motor Vehicle Air Conditioners (MVACs) retrofitted to use a... respondents: 294 (total). Frequency of response: Once per retrofit of a motor vehicle air conditioner. Total... Request; Comment Request; EPA-ICR No. 1774.05--Mobile Air Conditioner Retrofitting Program AGENCY...

Experimental performance of R432A to replace R22 in residential air-conditioners and heat pumps

International Nuclear Information System (INIS)

Park, Ki-Jung; Shim, Yun-Bo; Jung, Dongsoo

2009-01-01

In this study, thermodynamic performance of R432A and HCFC22 is measured in a heat pump bench tester under both air-conditioning and heat pumping conditions. R432A has no ozone depletion potential and very low greenhouse warming potential of less than 5. R432A also offers a similar vapor pressure to HCFC22 for 'drop-in' replacement. Test results showed that the coefficient of performance and capacity of R432A are 8.5-8.7% and 1.9-6.4% higher than those of HCFC22 for both conditions. The compressor discharge temperature of R432A is 14.1-17.3 deg. C lower than that of HCFC22 while the amount of charge for R432A is 50% lower than that of HCFC22 due to its low density. Overall, R432A is a good long term 'drop-in' environmentally friendly alternative to replace HCFC22 in residential air-conditioners and heat pumps due to its excellent thermodynamic and environmental properties

Effects of a non-rinse conditioner on the enamel of primary teeth

Directory of Open Access Journals (Sweden)

Fava Marcelo

2003-01-01

Full Text Available The aim of this in vitro study was to evaluate by scanning electron microscopy the morphological aspects of the enamel of primary teeth after etching with 36% phosphoric acid or a non-rinse conditioner. Ten naturally exfoliated anterior primary teeth were selected. The samples were subjected to prophylaxis with pumice paste and water using a low-speed hand piece. Etching was done on the buccal surface. Specimens were divided into 2 groups: G1 (n=10: etching with 36% phosphoric acid gel - Conditioner 36 (Dentsply for 20 s, followed by water rinse for 15 s; G2 (n=10: etching with NRC - Non Rinse Conditioner (Dentsply for 20 s, followed by air drying for 15 s. The samples were dehydrated, mounted on metal stubs, coated with gold and observed with Jeol JSM-6100 scanning electron microscope. Electron-micrographic analysis showed that both etching agents were effective for etching the enamel of primary teeth causing the formation of microporosities on the enamel surface, although the etching pattern was more effective with the use of 36% phosphoric acid gel.

Cooling the Planet: Opportunities for Deployment of Superefficient Room Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Waide, Paul [Navigant Consulting Inc., Chicago, IL (United States); Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-04-01

This report presents the results of an analysis, commissioned by the U.S. Department of Energy, of Air Conditioner (AC) efficiency in support of the Super-efficient Equipment and Appliance Deployment (SEAD) initiative.1 The International Energy Studies group at Lawrence Berkeley National Laboratory in collaboration with Navigant Consulting Inc. performed the analysis. SEAD aims to transform the global market by increasing the penetration of highly efficient equipment and appliances. SEAD partners work together in voluntary activities to: (1) “raise the efficiency ceiling” by pulling superefficient appliances and equipment into the market through cooperation on measures like incentives, procurement, awards, and research and development (R&D) investments; (2) “raise the efficiency floor” by working together to bolster national or regional policies like minimum efficiency standards; and (3) “strengthen the efficiency foundations” of programs by coordinating technical work to support these activities.2 The objective of this analysis is to provide the background technical information necessary to improve the efficiency of ACs and to provide a foundation for the activities of SEAD participating countries. We find that even the best currently available technology offers large efficiency improvement opportunities (35% to 50% reduction in energy consumption from the market average) in most SEAD countries. The cost effective efficiency improvements range from 20% to 30% reduction in energy consumption based on a consumer perspective.

Performance computation of window air conditioner with very low GWP near azeotropic refrigerant mixtures as a drop in Substitutes to R22

Directory of Open Access Journals (Sweden)

Vali Shaik Sharmas

2018-01-01

Full Text Available The principal objective of the present study is to compute the thermodynamic performance of window air conditioner based on standard vapour compression refrigeration cycle using R22, R407C and nineteen refrigerant mixtures. In this work nineteen R290/R1270 blends at different compositions are developed. A MATLAB code is developed to compute the thermodynamic performance parameters of all the studied refrigerants at condensing and evaporating temperatures of 54.4°C and 7.2°C respectively. The performance parameters are cooling effect, compressor work, COP, compressor discharge temperature, power per ton of refrigeration and volumetric cooling capacity respectively. Analytical results revealed that COP of new binary mixture R290/R1270 (90/10 by mass % is 2.82% higher among R22, R407C and nineteen studied refrigerants. Energy required by the compressor per ton of refrigeration for R290/R1270 (90/10 by mass % is 2.73% lower among R22, R407C and nineteen studied fluids. The discharge temperature of the compressor for all the nineteen investigated blends are reduced by 6.0-8.9oC compared to R22. Overall thermodynamic performance of window air conditioner with R290/R1270 (90/10 by mass % is better than R22 with significant savings in energy consumption and hence it is an energy efficient ecofriendly refrigerant mixture as a drop in substitute to R22.

Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner.

Science.gov (United States)

Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

2011-01-15

Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor. Copyright © 2010 Elsevier B.V. All rights reserved.

Power conditioner without isolation transformer; Toransuresu power conditioner no shohin kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Okado, C; Itami, T; Kimoto, K [Toshiba Corp., Tokyo (Japan)

1996-10-27

A light-weight downsized and high efficiency transformer-less type 4 kW power conditioner (inverter) has been developed. This power conditioner insures the system interconnection protection by monitoring the voltage of two single-phase three-line circuits. The power conditioner has weight of 17.5 kg and efficiency of 94%. Potential fluctuation of photovoltaic cells due to the switching of power devices at the inverter was reduced. Output capacity was reduced in the low input voltage range. Outflow of DC component was prevented in high accuracy by usually correcting the zero point drift of detector, and by using the current detector with excellent linearity. To detect the DC ground fault, and to trip the output side breaker locating at the ground fault current pass, a zero phase converter detection circuit has been developed, by which the DC component can be detected at the DC input side. As a result of performance verification, the efficiency, power factor, EMI level, protection of outflow of DC component, protection of ground fault, protection of single operation detection, and noise level were satisfied. This system is prospective for the diffusion of photovoltaic power generation in the future. 3 refs., 8 figs., 1 tab.

Desiccation induces accumulations of antheraxanthin and zeaxanthin in intertidal macro-alga Ulva pertusa (Chlorophyta.

Directory of Open Access Journals (Sweden)

Xiujun Xie

Full Text Available For plants and algae, exposure to high light levels is deleterious to their photosynthetic machineries. It also can accelerate water evaporation and thus potentially lead to drought stress. Most photosynthetic organisms protect themselves against high light caused photodamages by xanthophyll cycle-dependent thermal energy dissipation. It is generally accepted that high light activates xanthophyll cycle. However, the relationship between xanthophyll cycle and drought stress remains ambiguous. Herein, Ulva pertusa (Chlorophyta, a representative perennial intertidal macro-algae species with high drought-tolerant capabilities and simple structures, was used to investigate the operation of xanthophyll cycle during desiccation in air. The results indicate that desiccation under dim light induced accumulation of antheraxanthin (Ax and zeaxanthin (Zx at the expense of violaxanthin (Vx. This accumulation could be arrested by dithiothreitol completely and by uncoupler (carbonyl cyanide p-trifluoromethoxyphenylhydrazone partially, implying the participation of Vx de-epoxidase in conversion of Vx to Ax and Zx. Treatment with inhibitors of electron transport along thylakoid membrane, e.g. DCMU, PG and DBMIB, did not significantly arrest desiccation-induced accumulation of Ax and Zx. We propose that for U. pertusa, besides excess light, desiccation itself could also induce accumulation of Ax and Zx. This accumulation could proceed without electron transport along thylakoid membrane, and is possibly resulting from the reduction of thylakoid lumen volume during desiccation. Considering the pleiotropic effects of Ax and Zx, accumulated Ax and Zx may function in protecting thylakoid membrane and enhancing thermal quenching during emersion in air.

Technical and Economic Aspects of Designing an Efficient Room Air-Conditioner Program in India

Energy Technology Data Exchange (ETDEWEB)

Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.; Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.; Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.; Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Div.

2017-09-05

Several studies have projected a massive increase in the demand for air conditioners (ACs) over the next two decades in India. By 2030, room ACs could add 140 GW to the peak load, equivalent to over 30% of the total projected peak load. Therefore, there is significant interest among policymakers, regulators, and utilities in managing room AC demand by enhancing energy efficiency. Building on the historical success of the Indian Bureau of Energy Efficiency’s star-labeling program, Energy Efficiency Services Limited recently announced a program to accelerate the sale of efficient room ACs using bulk procurement, similar to their successful UJALA light-emitting diode (LED) bulk procurement program. This report discusses some of the key considerations in designing a bulk procurement or financial incentive program for enhancing room AC efficiency in India. We draw upon our previous research to demonstrate the overall technical potential and price impact of room AC efficiency improvement and its technical feasibility in India. We also discuss the importance of using low global warming potential (GWP) refrigerants and smart AC equipment that is demand response (DR) ready.

Lemongrass-Incorporated Tissue Conditioner Against Candida albicans Culture

Science.gov (United States)

Amornvit, Pokpong; Srithavaj, Theerathavaj

2014-01-01

Background: Tissue conditioner is applied popularly with dental prosthesis during wound healing process but it becomes a reservoir of oral microbiota, especially Candida species after long-term usage. Several antifungal drugs have been mixed with this material to control fungal level. In this study, lemongrass essential oil was added into COE-COMFORT tissue conditioner before being determined for anti-Candida efficacy. Materials and Methods: Lemongrass (Cymbopogon citratus) essential oil was primarily determined for antifungal activity against C. albicans American type culture collection (ATCC) 10231 and MIC (minimum inhibitory concentration) value by agar disk diffusion and broth microdilution methods, respectively. COE-COMFORT tissue conditioner was prepared as recommended by the manufacturer after a fixed volume of the oil at its MIC or higher concentrations were mixed thoroughly in its liquid part. Antifungal efficacy of the tissue conditioner with/without herb was finally analyzed. Results: Lemongrass essential oil displayed potent antifungal activity against C. albicans ATCC 10231and its MIC value was 0.06% (v/v). Dissimilarly, the tissue conditioner containing the oil at MIC level did not cease the growth of the tested fungus. Both reference and clinical isolates of C. albicans were completely inhibited after exposed to the tissue conditioner containing at least 0.25% (v/v) of the oil (approximately 4-time MIC). The tissue conditioner without herb or with nystatin was employed as negative or positive control, respectively. Conclusion: COE-COMFORT tissue conditioner supplemented with lemongrass essential oil obviously demonstrated another desirable property as in vitro anti-Candida efficacy to minimize the risk of getting Candidal infection. PMID:25177638

Theoretical study on volatile organic compound removal and energy performance of a novel heat pump assisted solid desiccant cooling system

DEFF Research Database (Denmark)

Nie, Jinzhe; Fang, Lei; Zhang, Ge

2015-01-01

for cooling, dehumidification and indoor air cleaning in normal office, commercial or residential buildings. The desiccant rotor was used for dehumidification and indoor air cleaning; the heat pump provided sensible cooling and regeneration heat for the desiccant rotor. The theoretical model consisted of two...... and predicted. The theoretical model was validated by experimental data. Validating results showed that the model could be used to predict the performance of HP-SDC. The results also showed that the HP-SDC could clean air borne contaminants effectively and could provide an energy efficient choice...

Roseomonas aerofrigidensis sp. nov., isolated from an air conditioner.

Science.gov (United States)

Hyeon, Jong Woo; Jeon, Che Ok

2017-10-01

A Gram-stain-negative, strictly aerobic bacterium, designated HC1 T , was isolated from an air conditioner in South Korea. Cells were orange, non-motile cocci with oxidase- and catalase-positive activities and did not contain bacteriochlorophyll a. Growth of strain HC1 T was observed at 10-45 °C (optimum, 30 °C), pH 4.5-9.5 (optimum, pH 7.0) and 0-3 % (w/v) NaCl (optimum, 0 %). Strain HC1 T contained summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0 and cyclo-C19 : 0ω8c as the major fatty acids and ubiquinone-10 as the sole isoprenoid quinone. Phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unknown aminolipid were detected as the major polar lipids. The major carotenoid was hydroxyspirilloxanthin. The G+C content of the genomic DNA was 70.1 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain HC1 T formed a phylogenetic lineage within the genus Roseomonas. Strain HC1 T was most closely related to the type strains of Roseomonas oryzae, Roseomonas rubra, Roseomonas aestuarii and Roseomonas rhizosphaerae with 98.1, 97.9, 97.6 and 96.8 % 16S rRNA gene sequence similarities, respectively, but the DNA-DNA relatedness values between strain HC1 T and closely related type strains were less than 70 %. Based on phenotypic, chemotaxonomic and molecular properties, strain HC1 T represents a novel species of the genus Roseomonas, for which the name Roseomonas aerofrigidensis sp. nov. is proposed. The type strain is HC1 T (=KACC 19097 T =JCM 31878 T ).

Experimental Validation of the Simulation Model of a DOAS Equipped with a Desiccant Wheel and a Vapor Compression Refrigeration System

Directory of Open Access Journals (Sweden)

Pedro J. Martínez

2017-09-01

Full Text Available A dedicated outdoor air system (DOAS can be designed to supply 100% of the outside air and meet the latent load of the room with dry air. The objectives of this study were to develop a model of a DOAS equipped with a desiccant wheel and a vapor-compression refrigeration system, build a prototype, validate the model with experimental data, and gain knowledge about the system operation. The test facility was designed with the desiccant wheel downstream of the cooling coil to take advantage of the operating principles of cooling coils and desiccants. A model of the DOAS was developed in the TRNSYS environment. The root mean standard error (RMSE was used for model validation by comparing the measured air and refrigerant properties with the corresponding calculated values. The results obtained with the developed model showed that the DOAS was able to maintain an indoor humidity ratio depending on outdoor conditions. Laboratory tests were also used to investigate the effect of changes in the regeneration air temperature and the process airflow rate on the process air humidity ratio at the outlet of the wheel. The results are consistent with the technical literature.

Advanced air detritiation dryer

International Nuclear Information System (INIS)

Anon.

1989-01-01

The isotopic exchange principle has proved effective in increasing air detritiation factors of atmospheric dryers. A CFFTP/AECL Chalk River program has demonstrated detritiation factors of 100,000 in trials. The technology is designed for application on regenerating atmospheric dryers using molecular sieve desiccant beds, used in rooms likely to encounter airborne tritium contamination. Dryer design concepts for dryers at JET (Joint European Torus, England) and ITER have been prepared by Alan Dombra of AECL, using the isotopic exchange technology. The isotopic exchange method works by passing tritiated air over a detritiated desiccant bed. Airborne tritium atoms are exchanged in the bed for ordinary hydrogen atoms from the bed's residual moisture loading. Tritium remains on the bed until it is discharged in a regeneration cycle. During regeneration, the desiccant bed is first heated with hot, dry air to drive off collected tritiated moisture. Airborne tritium removed from the air is collected as a tritiated water distillate and stored for later processing. During the second part of the regeneration cycle, the desiccant bed is washed with clean moist air to elute remaining traces of tritium and to refresh the bed to ready it for another tritium absorption period

Performance of R433A for replacing HCFC22 used in residential air-conditioners and heat pumps

International Nuclear Information System (INIS)

Park, Ki-Jung; Shim, Yun-Bo; Jung, Dongsoo

2008-01-01

In this study, thermodynamic performance of R433A and HCFC22 is measured in a heat pump bench tester under air-conditioning and heat pumping conditions. R433A has no ozone depletion potential and very low greenhouse warming potential of less than 5. R433A also offers a similar vapor pressure to HCFC22 for possible 'drop-in' replacement. Test results showed that the coefficient of performance of R433A is 4.9-7.6% higher than that of HCFC22 while the capacity of R433A is 1.0-5.5% lower than that of HCFC22 for both conditions. The compressor discharge temperature of R433A is 22.6-27.9 deg. C lower than that of HCFC22 while the amount of charge for R433A is 57.0-57.7% lower than that of HCFC22 due to its low density. Overall, R433A is a good long term environmentally friendly alternative to replace HCFC22 in residential air-conditioners and heat pumps due to its excellent thermodynamic and environmental properties with minor adjustments

Cost-Benefit of Improving the Efficiency of Room Air Conditioners (Inverter and Fixed Speed) in India

Energy Technology Data Exchange (ETDEWEB)

Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Diddi, Saurabh [Bureau of Energy Efficiency, Government of India (India); Ahuja, Deepanshu [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Mukherjee, P. K. [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Walia, Archana [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States)

2016-06-01

Improving efficiency of air conditioners (ACs) typically involves improving the efficiency of various components such as compressors, heat exchangers, expansion valves, refrigerant,and fans. We estimate the incremental cost of improving the efficiency of room ACs based on the cost of improving the efficiency of its key components. Further, we estimate the retail price increase required to cover the cost of efficiency improvement, compare it with electricity bill savings, and calculate the payback period for consumers to recover the additional price of a more efficient AC. The finding that significant efficiency improvement is cost effective from a consumer perspective is robust over a wide range of assumptions. If we assume a 50% higher incremental price compared to our baseline estimate, the payback period for the efficiency level of 3.5 ISEER is 1.1 years. Given the findings of this study, establishing more stringent minimum efficiency performance criteria (one-star level) should be evaluated rigorously considering significant benefits to consumers, energy security, and environment

Modelagem de um condicionador de ar de alta precisão para uso em processamento agrícola Modeling of a high precision air conditioner for use in agricultural processing

Directory of Open Access Journals (Sweden)

Mauri Fortes

2006-08-01

Full Text Available Apresenta-se neste trabalho, estudo detalhado sobre a modelagem de um condicionador de ar com controle acurado de temperatura e umidade relativa. Desenvolveu-se um programa de computador que permite predizer o comportamento do sistema sob diferentes condições psicrométricas e de vazão do ar de entrada. O modelo global físico-matemático inclui equações de balanço de massa e de energia para três diferentes volumes de controle que compõem o condicionador. Modelaram-se os processos de mistura, evaporação (ou condensação simultânea de uma superfície d'água e de uma gota e o aquecimento de corrente de ar, separadamente. Propõem-se expressões semi-empíricas simples para os coeficientes de transferência de calor e massa inerentes ao processo de evaporação sobre uma superfície d'água e um modelo simplificado para o sistema de spray. Construiu-se um condicionador de ar no qual foram feitos testes experimentais para o ajuste das constantes que aparecem nas expressões para os coeficientes de transferência. Os dados obtidos validaram o modelo global, com precisão aceitável para projetos de engenharia.In this work, a detailed procedure for the analysis of an accurately controlled air conditioner is presented. A computer program, that allows predicting the behavior of the system under different psychrometric conditions and different input air mass flow rates, was developed. The global physical-mathematical model includes mass and energy conservation equations for three different control volumes that compose the conditioner. Thus, the processes of mixture of air, simultaneous evaporation (or condensation from a water surface and from a drop, and the air-stream heating are modeled separately. Simple semi-empiric expressions for heat and mass coefficients inherent to the evaporation process on a water surface are proposed as well a simplified model for the spray system. Experimental tests made on an air-conditioner allowed to obtain

Mass transfer performance comparison of two commonly used liquid desiccants: LiBr and LiCl aqueous solutions

International Nuclear Information System (INIS)

Liu, X.H.; Yi, X.Q.; Jiang, Y.

2011-01-01

Mass transfer performance of two commonly used liquid desiccants, LiBr aqueous solution and LiCl aqueous solution, is compared in this paper on the basis of the same solution temperature and surface vapor pressure. According to the analysis of the analytical solutions of heat and mass transfer processes, the key performance influencing factors are heat capacity ratio of air to desiccant m * and mass transfer unit NTU m . The heat capacities of the two liquid desiccants are about the same at same volumetric flow rate, and LiBr solution has higher density and smaller specific heat capacity. The variance of mass transfer unit with different operating conditions and liquid desiccants are derived based on the experimental results. In the condition of the same desiccant mass flow rate, the dehumidification performance of LiCl solution is better, and the regeneration performance of LiBr solution is a little better or almost the same as that of LiCl solution. In the condition of the same desiccant volumetric flow rate, the dehumidification performance of LiCl solution is a little better or about the same compared with LiBr solution, and the regeneration performance of LiBr solution is better. The COPs of the liquid desiccant systems using these two desiccants are similar; while LiCl solution costs 18% lower than LiBr solution at current Chinese price.

Biosentinel: Improving Desiccation Tolerance of Yeast Biosensors for Deep-Space Missions

Science.gov (United States)

Dalal, Sawan; Santa Maria, Sergio R.; Liddell, Lauren; Bhattacharya, Sharmila

2017-01-01

BioSentinel is one of 13 secondary payloads to be deployed on Exploration Mission 1 (EM-1) in 2019. We will use the budding yeast Saccharomyces cerevisiae as a biosensor to determine how deep-space radiation affects living organisms and to potentially quantify radiation levels through radiation damage analysis. Radiation can damage DNA through double strand breaks (DSBs), which can normally be repaired by homologous recombination. Two yeast strains will be air-dried and stored in microfluidic cards within the payload: a wild-type control strain and a radiation sensitive rad51 mutant that is deficient in DSB repairs. Throughout the mission, the microfluidic cards will be rehydrated with growth medium and an indicator dye. Growth rates of each strain will be measured through LED detection of the reduction of the indicator dye, which correlates with DNA repair and the amount of radiation damage accumulated. Results from BioSentinel will be compared to analog experiments on the ISS and on Earth. It is well known that desiccation can damage yeast cells and decrease viability over time. We performed a screen for desiccation-tolerant rad51 strains. We selected 20 re-isolates of rad51 and ran a weekly screen for desiccation-tolerant mutants for five weeks. Our data shows that viability decreases over time, confirming previous research findings. Isolates L2, L5 and L14 indicate desiccation tolerance and are candidates for whole-genome sequencing. More time is needed to determine whether a specific strain is truly desiccation tolerant. Furthermore, we conducted an intracellular trehalose assay to test how intracellular trehalose concentrations affect or protect the mutant strains against desiccation stress. S. cerevisiae cell and reagent concentrations from a previously established intracellular trehalose protocol did not yield significant absorbance measurements, so we tested varying cell and reagent concentrations and determined proper concentrations for successful

Identification of proteins involved in desiccation tolerance in the red seaweed Pyropia orbicularis (Rhodophyta, Bangiales).

Science.gov (United States)

López-Cristoffanini, Camilo; Zapata, Javier; Gaillard, Fanny; Potin, Philippe; Correa, Juan A; Contreras-Porcia, Loretto

2015-12-01

Extreme reduction in cellular water content leads to desiccation, which, if persistent, affects the physiology of organisms, mainly through oxidative stress. Some organisms are highly tolerant to desiccation, including resurrection plants and certain intertidal seaweeds. One such species is Pyropia orbicularis, a rhodophycean that colonizes upper intertidal zones along the Chilean coast. Despite long, daily periods of air exposure due to tides, this alga is highly tolerant to desiccation. The present study examined the proteome of P. orbicularis by 2DE and LC-MS/MS analyses to determine the proteins associated with desiccation tolerance (DT). The results showed that, under natural conditions, there were significant changes in the protein profile during low tide as compared to naturally hydrated plants at high tide. These changes were mainly in newly appeared proteins spots such as chaperones, monodehydroascorbate reductase, and manganese superoxide dismutase, among others. Previously undescribed proteins under desiccation conditions included phycobiliproteins, glyoxalase I, and phosphomannomutase. These changes evidenced that several physiological responses involved in DT are activated during low tide, including decreased photosynthetic activity, increased antioxidant capacity, and the preservation of cell physiology by regulating water content, cell wall structure, and cell volume. Similar responses have been observed in resurrection plants and bryophytes exposed to desiccation. Therefore, the coordinated activation of different desiccation tolerance pathways in P. orbicularis could explain the successful biological performance of this seaweed in the upper intertidal rocky zones. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sugars and Desiccation Tolerance in Seeds 1

Science.gov (United States)

Koster, Karen L.; Leopold, A. Carl

1988-01-01

Soluble sugars have been shown to protect liposomes and lobster microsomes from desiccation damage, and a protective role has been proposed for them in several anhydrous systems. We have studied the relationship between soluble sugar content and the loss of desiccation tolerance in the axes of germinating soybean (Glycine max L. Merr. cv Williams), pea (Pisum sativum L. cv Alaska), and corn (Zea mays L. cv Merit) axes. The loss of desiccation tolerance during imbibition was monitored by following the ability of seeds to germinate after desiccation following various periods of preimbibition and by following the rates of electrolyte leakage from dried, then rehydrated axes. Finally, we analyzed the soluble sugar contents of the axes throughout the transition from desiccation tolerance to intolerance. These analyses show that sucrose and larger oligosaccharides were consistently present during the tolerant stage, and that desiccation tolerance disappeared as the oligosaccharides were lost. The results support the idea that sucrose may serve as the principal agent of desiccation tolerance in these seeds, with the larger oligosaccharides serving to keep the sucrose from crystallizing. PMID:16666392

Cover Your Cough! A Short and Simple Activity to Demonstrate the Antimicrobial Effect of Desiccation

Directory of Open Access Journals (Sweden)

Jennifer Cook Easterwood

2013-08-01

Full Text Available Many undergraduate microbiology laboratory manuals include exercises demonstrating the antimicrobial effects of physical agents, such as UV light and heat, and chemical agents, such as disinfectants and antibiotics (3, 4. There is, however, a lack of exercises examining the effects of desiccation on bacterial growth and survival. This particular form of antimicrobial control is especially relevant today with an increased emphasis on coughing and sneezing into one’s sleeve or a tissue, where microbes will not contaminate hands and will eventually desiccate and die (2. Desiccation can have bacteriostatic or bactericidal effects depending on the species, the material on which the organism has desiccated, and the length of time. The absence of water can damage many cellular components, including enzymes, nucleic acids, and cell membranes (1. However, many prokaryotes have some degree of resistance to desiccation, with Escherichia coli surviving around 24 hours and Bacillus species surviving upwards of 300 years, though these numbers can vary due to a number of confounding factors (5. Some of these factors include the method by which desiccation occurred, whether desiccation occurred in a natural or laboratory situation, and the species itself (5. To address the effects of desiccation on bacterial growth and survival, a short, simple exercise was developed. By inoculating various materials with bacterial cultures and allowing them to air-dry for 24 hours, students can visualize the effects of desiccation by analyzing the growth, or lack thereof, when organisms are transferred to nutrient agar plates. This exercise has been used in a health professions microbiology course as well as a microbiology course for biology and biochemistry majors. It is short enough to be conducted during a standard lecture period or during a longer laboratory period in conjunction with other experiments demonstrating the effectiveness of physical agents on microbial

Experimental and Numerical Investigations of Soil Desiccation for Vadose Zone Remediation: Report for Fiscal Year 2007

Energy Technology Data Exchange (ETDEWEB)

Ward, Andy L.; Oostrom, Mart; Bacon, Diana H.

2008-02-04

Apart from source excavation, the options available for the remediation of vadose zone metal and radionuclide contaminants beyond the practical excavation depth (0 to 15 m) are quite limited. Of the available technologies, very few are applicable to the deep vadose zone with the top-ranked candidate being soil desiccation. An expert panel review of the work on infiltration control and supplemental technologies identified a number of knowledge gaps that would need to be overcome before soil desiccation could be deployed. The report documents some of the research conducted in the last year to fill these knowledge gaps. This work included 1) performing intermediate-scale laboratory flow cell experiments to demonstrate the desiccation process, 2) implementing a scalable version of Subsurface Transport Over Multiple Phases–Water-Air-Energy (STOMP-WAE), and 3) performing numerical experiments to identify the factors controlling the performance of a desiccation system.

Performance of a desiccant assisted packed bed passive solar dryer for copra processing

Directory of Open Access Journals (Sweden)

Padmanaban Govindarajulu

2017-01-01

Full Text Available In this paper, the performance of a novel desiccant assisted packed bed passive solar dryer was evaluated for copra processing and compared with conventional passive solar dryer. This novel solar dryer consists of a desiccant assisted packed bed solar air heater attached with a dryer cabin. The desiccant and phase change materials packed in the solar air heater has control the humidity and retains the heat for longer duration, respectively. The performance of the dryer was evaluated (in terms of drying time to attain the final equilibrium moisture content, drying rate, specific moisture extraction rate, pick-up efficiency, and dryer efficiency under the meteorological conditions of Coimbatore city in India during March and April 2016. The copra was dried from initial moisture content (wet basis of about 52% to the final moisture content (wet basis of about 8% in 62 hours with specific moisture extraction rate of 0.82 kg/kWh. The drying time was reduced by about 44 hours when compared to the conventional passive solar dryer. The dryer pick-up efficiency was varied between about 10% and 65%. The average dryer thermal efficiency was calculated to be about 32%. The quality of final dried product was found to be good.

Residential Pre-Cooling: Mechanical Cooling and Air-Side Economizers:

OpenAIRE

Turner, William J.N; Walker, Iain S.; Roux, Jordan

2012-01-01

This study used an advanced airflow, energy and humidity modeling tool to evaluate residential air-side economizers and mechanical pre-cooling strategies using the air conditioner, in all US DOE Climate Zones for a typical new home with ASHRAE Standard 62.2 compliant ventilation. A residential air-side economizer is a large supply fan used for night ventilation. Mechanical pre-cooling used the building air conditioner operating at lower than usual set before the peak demand period. The simula...

21 CFR 872.3750 - Bracket adhesive resin and tooth conditioner.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bracket adhesive resin and tooth conditioner. 872... SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3750 Bracket adhesive resin and tooth conditioner. (a) Identification. A bracket adhesive resin and tooth conditioner is a device...

Documenting the Effectiveness of Cosorption of Airborne Contaminants by a Field-Installed Active Desiccant System: Final Report - Phase 2D

Energy Technology Data Exchange (ETDEWEB)

Fischer, J

2003-01-23

The final report for Phase 1 of this research effort (ORNL/SUB/94-SV004/1) concluded that a significant market opportunity would exist for active desiccant systems if it could be demonstrated that they can remove a significant proportion of common airborne contaminants while simultaneously performing the primary function of dehumidifying a stream of outdoor air or recirculated building air. If the engineering community begins to follow the intent of ASHRAE Standard 62, now part of all major building codes, the outdoor air in many major cities may need to be pre-cleaned before it is introduced into occupied spaces. Common air contaminant cosorption capability would provide a solution to three important aspects of the ASHRAE 62-89 standard that have yet to be effectively addressed by heating, ventilation, and air-conditioning (HVAC) equipment manufacturers: (1) The ASHRAE standard defines acceptable outdoor air quality. If the outdoor air contains unacceptable levels of certain common outdoor air contaminants (e.g., sulfur dioxide, ozone), then the standard requires that these contaminants be removed from the outdoor air stream to reach compliance with the acceptable outdoor air quality guidelines. (2) Some engineers prefer to apply a filtration or prescriptive approach rather than a ventilation approach to solving indoor air quality problems. The ASHRAE standard recognizes this approach provided that the filtration technology exists to remove the gaseous contaminants encountered. The performance of current gaseous filtration technologies is not well documented, and they can be costly to maintain because the life of the filter is limited and the cost is high. Moreover, it is not easy to determine when the filters need changing. In such applications, an additional advantage provided by the active desiccant system would be that the same piece of equipment could control space humidity and provide filtration, even during unoccupied periods, if the active desiccant system

Performance improvement of air-cooled refrigeration system by using evaporatively cooled air condenser

Energy Technology Data Exchange (ETDEWEB)

Hajidavalloo, E.; Eghtedari, H. [Mechanical Engineering Department, Shahid Chamran University, Golestan St., Ahvaz (Iran)

2010-08-15

Increasing the coefficient of performance of air conditioner with air-cooled condenser is a challenging problem especially in area with very hot weather conditions. Application of evaporatively cooled air condenser instead of air-cooled condenser is proposed in this paper as an efficient way to solve the problem. An evaporative cooler was built and coupled to the existing air-cooled condenser of a split-air-conditioner in order to measure its effect on the cycle performance under various ambient air temperatures up to 49 C. Experimental results show that application of evaporatively cooled air condenser has significant effect on the performance improvement of the cycle and the rate of improvement is increased as ambient air temperature increases. It is also found that by using evaporatively cooled air condenser in hot weather conditions, the power consumption can be reduced up to 20% and the coefficient of performance can be improved around 50%. More improvements can be expected if a more efficient evaporative cooler is used. (author)

Effects of Desiccation Practices of Cultured Atlantic Oysters (Crassostrea virginica) on Vibrio spp. in Portersville Bay, Alabama, USA.

Science.gov (United States)

Grodeska, Stephanie M; Jones, Jessica L; Arias, Covadonga R; Walton, William C

2017-08-01

The expansion of off-bottom aquaculture to the Gulf of Mexico has raised public health concerns for human health officials. High temperatures in the Gulf of Mexico are associated with high levels of Vibrio parahaemolyticus and Vibrio vulnificus. Routine desiccation practices associated with off-bottom aquaculture expose oysters to ambient air, allowing Vibrio spp. to proliferate in the closed oyster. Currently, there is limited research on the length of time needed for Vibrio spp. levels in desiccated oysters to return to background levels, defined as the levels found in oysters that remain continually submersed and not exposed to ambient air. This study determined the time needed to return V. parahaemolyticus, V. vulnificus, and Vibrio cholerae levels to background levels in oysters exposed to the following desiccation practices: 3-h freshwater dip followed by 24-h ambient air exposure, 27-h ambient air exposure, and control. All oysters were submerged at least 2 weeks prior to the beginning of each trial, with the control samples remaining submerged for the duration of each trial. Vibrio spp. levels were enumerated from samples collected on days 0, 1, 2, 3, 7, 10, and 14 after resubmersion using a three-tube most-probable-number enrichment followed by BAX PCR. V. cholerae levels were frequently (92%) below the limit of detection at all times, so they were not statistically analyzed. V. parahaemolyticus and V. vulnificus levels in the 27-h ambient air exposure and the 3-h freshwater dip followed by 24-h ambient air exposure samples were significantly elevated compared with background samples. In most cases, the Vibrio spp. levels in oysters in both desiccation treatments remained elevated compared with background levels until 2 or 3 days post-resubmersion. However, there was one trial in which the Vibrio spp. levels did not return to background levels until day 7. The results of this study provide scientific support that oyster farmers should be required to

Modeling of a regenerative indirect evaporative cooler for a desiccant cooling system

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Reinholdt, Lars O.

This paper presents a numerical study of a regenerative indirect evaporative cooler, the so-called Dew Point Cooler (DPC), which is part of a Desiccant Cooling system that may both dehumidify and cool humid air. The DPC model is based on first principles using a 1D finite volume scheme...

Improved climatic chamber for desiccation simulation

Directory of Open Access Journals (Sweden)

Lozada Catalina

2016-01-01

Full Text Available The climatic chamber at the Universidad de Los Andes was improved for modeling desiccation in soil layers. This chamber allows the measurement of different environmental variables. In this research, evaporation tests were conducted in water imposing boundary conditions for drying, and then these tests were performed in a soil layer. The soil was prepared from a slurry state and was drying controlling the temperature, the infrared radiation, the wind velocity, and the relative humidity. In the first part of this paper, a description of the climatic chamber, operation ranges and theoretical work principles of the climatic chamber are presented. Then, the second part shows the results for desiccation in water and soil. The desiccation tests performed with the climatic chamber allow simulating all environmental conditions accurately during drying coupling the effect of all environmental variables. As a result, the evaporation rate increases with infrared radiation in soil and water. The rate at the beginning of the desiccation tests in clays is the same as in water. However, this evaporation rate decreases as the soil becomes desiccated.

Incidence of polybrominated diphenyl ethers in central air conditioner filter dust from a new office building.

Science.gov (United States)

Ni, Hong-Gang; Cao, Shan-Ping; Chang, Wen-Jing; Zeng, Hui

2011-07-01

This study examined polybrominated diphenyl ethers (PBDEs) in central air conditioner filter (CACF) dust from a new office building in Shenzhen, China. Human exposure to PBDE via dust inhalation and ingestion were also estimated. PBDEs level in CACF dust was lower than those in the other countries and regions. Approximately 0.671 pg/kg bw/day PM(2.5) (Particulate Matter up to 2.5 μm in size) bounded Σ(15)PBDEs can be inhaled deep into the lungs and 4.123 pg/kg bw/day PM(10) (Particulate Matter up to 10 μm in size) bounded Σ(15)PBDEs tend to be deposited in the upper parts of the respiratory system. The average total intake of Σ(15)PBDEs via dust inhalation and ingestion for adults reached ∼ 141 pg/kg bw/day in this building. This value was far below the reference dose (RfD) recommended by United States Environmental Protection Agency. Human exposure to PBDEs via dust inhalation and ingestion in the new building is less than the old ones. Copyright © 2010 Elsevier Ltd. All rights reserved.

Cost-Benefit of Improving the Efficiency of Room Air Conditioners (Inverter and Fixed Speed) in India

Energy Technology Data Exchange (ETDEWEB)

Shah, Nihar [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Abhyankar, Nikit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Park, Won Young [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Phadke, Amol [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Analysis and Environmental Impacts Division; Diddi, Saurabh [Government of India, New Delhi (India). Bureau of Energy Efficiency; Ahuja, Deepanshu [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Mukherjee, P. K. [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States); Walia, Archana [Collaborative Labeling and Appliance Standards Program (CLASP), Washington, DC (United States)

2016-06-30

Improving efficiency of air conditioners (ACs) typically involves improving the efficiency of various components such as compressors, heat exchangers, expansion valves, refrigerant and fans. We estimate the incremental cost of improving the efficiency of room ACs based on the cost of improving the efficiency of its key components. Further, we estimate the retail price increase required to cover the cost of efficiency improvement, compare it with electricity bill savings, and calculate the payback period for consumers to recover the additional price of a more efficient AC. We assess several efficiency levels, two of which are summarized below in the report. The finding that significant efficiency improvement is cost effective from a consumer perspective is robust over a wide range of assumptions. If we assume a 50% higher incremental price compared to our baseline estimate, the payback period for the efficiency level of 3.5 ISEER is 1.1 years. Given the findings of this study, establishing more stringent minimum efficiency performance criteria (one star level) should be evaluated rigorously considering significant benefits to consumers, energy security and environment.

Developing sporophytes transition from an inducible to a constitutive ecological strategy of desiccation tolerance in the moss Aloina ambigua: effects of desiccation on fitness.

Science.gov (United States)

Stark, Lloyd R; Brinda, John C

2015-03-01

Two ecological strategies of desiccation tolerance exist in plants, constitutive and inducible. Because of difficulties in culturing sporophytes, very little is known about desiccation tolerance in this generation and how desiccation affects sexual fitness. Cultured sporophytes and vegetative shoots from a single genotype of the moss Aloina ambigua raised in the laboratory were tested for their strategy of desiccation tolerance by desiccating the shoot-sporophyte complex and vegetative shoots at different intensities, and comparing outcomes with those of undried shoot-sporophyte complexes and vegetative shoots. By using a dehardened clonal line, the effects of field, age and genetic variance among plants were removed. The gametophyte and embryonic sporophyte were found to employ a predominantly inducible strategy of desiccation tolerance, while the post-embryonic sporophyte was found to employ a moderately constitutive strategy of desiccation tolerance. Further, desiccation reduced sporophyte fitness, as measured by sporophyte mass, seta length and capsule size. However, the effects of desiccation on sporophyte fitness were reduced if the stress occurred during embryonic development as opposed to postembryonic desiccation. The effects of desiccation on dehardened sporophytes of a bryophyte are shown for the first time. The transition from one desiccation tolerance strategy to the other in a single structure or generation is shown for only the second time in plants and for the first time in bryophytes. Finding degrees of inducible strategies of desiccation tolerance in different life phases prompts the formulation of a continuum hypothesis of ecological desiccation tolerance in mosses, where desiccation tolerance is not an either/or phenomenon, but varies in degree along a gradient of ecological inducibility. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email

Antifungal Effect of a Dental Tissue Conditioner Containing Nystatin-Loaded Alginate Microparticles.

Science.gov (United States)

Kim, Hyun-Jin; Son, Jun Sik; Kwon, Tae-Yub

2018-02-01

In this in vitro study, nystatin-alginate microparticles were successfully fabricated to control the release of nystatin from a commercial dental tissue conditioner. These nystatin-alginate microparticles were spherical and had a slightly rough surface. The microparticles incorporated into the tissue conditioner were distributed homogeneously throughout the tissue conditioner matrix. The incorporation of the microparticles did not deteriorate the mechanical properties of the original material. The agar diffusion test results showed that the tissue conditioner containing the microparticles had a good antifungal effect against Candida albicans. The nystatin-alginate microparticles efficiently controlled the release of nystatin from the tissue conditioner matrix over the experimental period of 14 days. Moreover, the nystatin-alginate microparticles incorporated in the tissue conditioner showed effective antifungal function even at lower concentrations of nystatin. The current study suggests that the tissue conditioner containing the nystatin-alginate microparticle carrier system has potential as an effective antifungal material.

Desiccation stress and tolerance in green algae: consequences for ultrastructure, physiological and molecular mechanisms

Science.gov (United States)

Holzinger, Andreas; Karsten, Ulf

2013-01-01

Although most green algae typically occur in aquatic ecosystems, many species also live partly or permanently under aeroterrestrial conditions, where the cells are exposed to the atmosphere and hence regularly experience dehydration. The ability of algal cells to survive in an air-dried state is termed desiccation tolerance. The mechanisms involved in desiccation tolerance of green algae are still poorly understood, and hence the aim of this review is to summarize recent findings on the effects of desiccation and osmotic water loss. Starting from structural changes, physiological, and biochemical consequences of desiccation will be addressed in different green-algal lineages. The available data clearly indicate a range of strategies, which are rather different in streptophycean and non-streptophycean green algae. While members of the Trebouxiophyceae exhibit effective water loss-prevention mechanisms based on the biosynthesis and accumulation of particular organic osmolytes such as polyols, these compounds are so far not reported in representatives of the Streptophyta. In members of the Streptophyta such as Klebsormidium, the most striking observation is the appearance of cross-walls in desiccated samples, which are strongly undulating, suggesting a high degree of mechanical flexibility. This aids in maintaining structural integrity in the dried state and allows the cell to maintain turgor pressure for a prolonged period of time during the dehydration process. Physiological strategies in aeroterrestrial green algae generally include a rapid reduction of photosynthesis during desiccation, but also a rather quick recovery after rewetting, whereas aquatic species are sensitive to drying. The underlying mechanisms such as the affected molecular components of the photosynthetic machinery are poorly understood in green algae. Therefore, modern approaches based on transcriptomics, proteomics, and/or metabolomics are urgently needed to better understand the molecular

Desiccation stress and tolerance in green algae: Consequences for ultrastructure, physiological and molecular mechanisms

Directory of Open Access Journals (Sweden)

Andreas eHolzinger

2013-08-01

Full Text Available Although most green algae typically occur in aquatic ecosystems, many species also live partly or permanently under aeroterrestrial conditions, where the cells are exposed to the atmosphere and hence regularly experience dehydration. The ability of algal cells to survive in an air-dried state is termed desiccation tolerance. The mechanisms involved in desiccation tolerance of green algae are still poorly understood, and hence the aim of this review is to summarize recent findings on the effects of desiccation and osmotic water loss. Starting from structural changes, physiological and biochemical consequences of desiccation will be addressed in different green-algal lineages. The available data clearly indicate a range of strategies, which are rather different in streptophycean and non-streptophycean green algae. For example, Trebouxiophyceae exhibit effective water loss-prevention mechanisms based on the biosynthesis and accumulation of particular organic osmolytes such as polyols, these compounds are so far not reported in representatives of the Streptophyta. In members of the Streptophyta such as Klebsormidium, the most striking observation is the appearance of cross-walls in desiccated samples, which are strongly undulating, suggesting a high degree of mechanical flexibility. This allows the cell to maintain turgor pressure for a prolonged period of time during the dehydration process. Physiological strategies in aeroterrestrial green algae generally include a rapid reduction of photosynthesis during desiccation, but also a rather quick recovery after rewetting, whereas aquatic species are sensitive to drying. The underlying mechanisms such as the affected molecular components of the photosynthetic machinery are poorly understood in green algae. Therefore, modern approaches based on transcriptomics, proteomics and/or metabolomics are urgently needed to better understand the molecular mechanisms involved in desiccation-stress physiology of

Formulation of humic-based soil conditioners

Science.gov (United States)

Amanova, M. A.; Mamytova, G. A.; Mamytova, B. A.; Kydralieva, K. A.; Jorobekova, Sh. J.

2009-04-01

The goal of the study is to prepare soil conditioners (SC) able to carry out the following functions: (i) the chemical conditioning of soil mainly comprising the adjustment of pH, (ii) the balancing of inorganic nutrients, (iii) the physical conditioning of soil mainly comprising the improvement of water permeability, air permeability and water retention properties, and (iv) improvement of the ecological system concerning of useful microorganisms activity in the soil. The SC was made of a mixture of inorganic ingredients, a chemical composition and physical and chemical properties of which promoted improvement of physical characteristic of soil and enrichment by its mineral nutritious elements. In addition to aforesaid ingredients, this soil conditioner contains agronomical-valued groups of microorganisms having the function promoting the growth of the crop. As organic component of SC humic acids (HA) was used. HA serve many major functions that result in better soil and plant health. In soil, HA can increase microbial and mycorrhizal activity while enhancing nutrient uptake by plant roots. HA work as a catalyst by stimulating root and plant growth, it may enhance enzymatic activity that in turn accelerates cell division which can lead to increased yields. HA can help to increase crop yields, seed germination, and much more. In short, humic acids helps keep healthy plants health. The first stage goal was to evaluate mineral and organic ingredients for formulation of SC. Soil conditioners assessed included ash and slag. The use of slags has been largelly used in agriculture as a source of lime and phosphoric acid. The silicic acid of slags reduces Al-acitivity thus, promoting a better assimilation of P-fertilizer by plants. Additionally, silicic acid is also known to improve soil moisture capacity, thus enhancing soil water availability to plants. Physico-chemical characteristics of ash and slag were determined, as a total - about 20 samples. Results include

Development of residential solar air conditioning system for electricity power peak cut 3

Energy Technology Data Exchange (ETDEWEB)

Yu, Gwon Jong [Korea Inst. of Energy and Resources, Daeduk (Korea, Republic of)

1995-12-31

In this research, the converter rectifier unit of the inverter air conditioner is substituted into the bidirectional PWM converter. The DC/DC power converter is established on the DC link between the photovoltaic array and the inverter air conditioner, and the photovoltaic air conditioning system which can be parallel driven which utility is developed. (author). 35 ref., 112 figs.

Swimming pools as heat sinks for air conditioners: Model design and experimental validation for natural thermal behavior of the pool

Energy Technology Data Exchange (ETDEWEB)

Woolley, Jonathan; Harrington, Curtis; Modera, Mark [University of California Davis, Western Cooling Efficiency Center, 1450 Drew Avenue, Suite 100, Davis, CA 95618 (United States)

2011-01-15

Swimming pools as thermal sinks for air conditioners could save approximately 40% on peak cooling power and 30% of overall cooling energy, compared to standard residential air conditioning. Heat dissipation from pools in semi-arid climates with large diurnal temperature shifts is such that pool heating and space cooling may occur concurrently; in which case heat rejected from cooling equipment could directly displace pool heating energy, while also improving space cooling efficiency. The performance of such a system relies on the natural temperature regulation of swimming pools governed by evaporative and convective heat exchange with the air, radiative heat exchange with the sky, and conductive heat exchange with the ground. This paper describes and validates a model that uses meteorological data to accurately predict the hourly temperature of a swimming pool to within 1.1 C maximum error over the period of observation. A thorough review of literature guided our choice of the most appropriate set of equations to describe the natural mass and energy exchange between a swimming pool and the environment. Monitoring of a pool in Davis, CA, was used to confirm the resulting simulations. Comparison of predicted and observed pool temperature for all hours over a 56 day experimental period shows an R-squared relatedness of 0.967. (author)

China Energy Efficiency Round Robin Testing Results for Room Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Zhou, Nan; Fridley, David; Zheng, Nina; Pierrot, Andre

2010-06-07

consuming products has always been an important component of all countries energy strategies. As we all know, a very large amount of total energy consumption is due to energy consuming products and equipment, which account for about 50% of China's total energy consumption. However, the current average energy utilization efficiency of this sector is only about 60%, 10 percent lower than the international advanced level. Therefore, China's energy consuming products and equipment sector holds great energy-saving potential. On the other hand, the energy supplied to these products is mainly from fossil fuel combustion, a major source of greenhouse gas (GHG) emissions. Therefore, improving the energy efficiency and augmenting the market share of market-dominant energy consuming products is of significant importance to achieving China's energy saving and emission reduction target and is an effective means to deal with energy and environmental constraints and climate change issues. Main energy consuming products generally include widely-used home appliances, industrial equipment, office equipment, transportation vehicles, etc. China is one of the major manufacturers and exporters of energy end-using products such as air-conditioners, refrigerators, televisions, etc. Their overall energy efficiency is comparatively low and the products are poorly designed, leading to great energy-saving potential. For example, electricity consumption of air conditioners accounts for about 20% of China's total electricity consumption and 40% of the summer electricity peak load in large and medium cities. However, less than 5% of units sold in the domestic market in 2009 reached the standard's highly efficient level of grade 2 above. The electricity consumption of electric motors and their related drive systems accounts for about 60% of China's total electricity consumption; however, less than 2% of the domestic market share consists of energy-efficient electric motor

Photovoltaic array: Power conditioner interface characteristics

Science.gov (United States)

Gonzalez, C. C.; Hill, G. M.; Ross, R. G., Jr.

1982-01-01

The electrical output (power, current, and voltage) of flat plate solar arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as dc-to-ac power conditioners must be capable of accommodating widely varying input levels while maintaining operation at or near the maximum power point of the array. The array operating characteristics and extreme output limits necessary for the systematic design of array load interfaces under a wide variety of climatic conditions are studied. A number of interface parameters are examined, including optimum operating voltage, voltage energy, maximum power and current limits, and maximum open circuit voltage. The effect of array degradation and I-V curve fill factor or the array power conditioner interface is also discussed. Results are presented as normalized ratios of power conditioner parameters to array parameters, making the results universally applicable to a wide variety of system sizes, sites, and operating modes.

Experimental investigation of a building integrated photovoltaic/thermal roof collector combined with a liquid desiccant enhanced indirect evaporative cooling system

International Nuclear Information System (INIS)

Buker, Mahmut Sami; Mempouo, Blaise; Riffat, Saffa B.

2015-01-01

Highlights: • Novel solar thermal collector for liquid desiccant air conditioning was introduced. • Low cost poly heat exchanger loop underneath the photovoltaic modules was proposed. • The ability of the combined system was experimentally investigated. • Water temperature in the loop could reach up to 35.5 °C during the tests. • This tri-gen system can supply 3 kW heating, 5.2 kW cooling and 10.3 MW h/year power. - Abstract: Large consumption of limited conventional fossil fuel resources, economic and environmental problems associated with the global warming and climate change have emphasized the immediate need to transition to renewable energy resources. Solar thermal applications along with renewable energy based cooling practices have attracted considerable interest towards sustainable solutions promising various technical, economic and environmental benefits. This study introduces a new concept on solar thermal energy driven liquid desiccant based dew point cooling system that integrates several green technologies; including photovoltaic modules, polyethylene heat exchanger loop and a combined liquid desiccant dehumidification-indirect evaporative air conditioning unit. A pilot scale experimental set-up was developed and tested to investigate the performance of the proposed system and influence of the various parameters such as weather condition, air flow and regeneration temperature. A cost effective, easy-to-make polyethylene heat exchanger loop was employed underneath PV panels for heat generation. In addition, a liquid desiccant enhanced dew point cooling unit was utilized to provide air conditioning through dehumidification of humid air and indirect evaporative cooling. The experimental results show that the proposed tri-generation system is capable of providing about 3 kW of heating, 5.2 kW of cooling power and 10.3 MW h/year power generation, respectively. The findings confirm the potential of the examined technology, and elucidate the

Use of dehumidifiers in desiccant cooling and dehumidification systems

International Nuclear Information System (INIS)

Van den Bulck, E.; Mitchell, J.W.; Klein, S.A.

1986-01-01

The use of rotary dehumidifiers in gas-fired open-cycle desiccant cooling systems is investigated by analyzing the performance of the rotary heat exchanger-rotary dehumidifier subsystem. For a given cooling load, the required regeneration heat supply can be minimized by choosing appropriate values for the regeneration air mass flow rate and the wheel rotation speed. A map is presented showing optimal values for rotational speed and regeneration flow rate as functions of the regeneration air inlet temperature and the process air inlet humidity ratio. This regeneration temperature is further optimized as a function of the process humidity ratio. In the analysis, the control strategy adjusts the process air mass flow rate to provide the required cooling load. Additional control options are considered and the sensitivity of the regeneration heat required to the wheel speed, regeneration air mass flow rate, and inlet temperature is discussed. Experimental data reported in the literature are compared with the analytical results and indicate good agreement

The study of desiccation-tolerance in drying leaves of the desiccation-tolerant grass Sporobolus elongatus and the desiccation-sensitive grass Sporobolus pyramidalis.

Science.gov (United States)

Ghasempour, Hamid Reza; Kianian, Jahanbakheshe

2007-03-01

Hydrated leaves of the resurrection grass Sporobolus elongatus are not desiccation tolerant (DT), but moderate to severe drought stress can induce their DT with the leaves remain attach to drying intact plants. In vivo protein synthesis was studied with SDS-page of extracts of leaves of intact drying plants of S. elongatus (a desiccation-Tolerant grass (DT)) and S. pyramidalis (a desiccation-sensitive species (DS)). Free proline increased in drying leaves. Soluble sugar contents also increased with drying but were less than fully hydrated leaves at 8% RWC. Total protein also showed an increase with an exception at 8% RWC which showed a decrease. SDS-page of extracts of drying leaves of both DT and DS plants were studied as relative water contents (RWC) decreased. In first phase, DT species at 58% RWC (80-51% RWC range), two proteins increased in contents. In the second phase, at 8% (35-4% RWC range) two new bands increased and two bands decreased. In leaves of DS species some bands decreased as drying progressed. Also, as drying advanced free proline increased in DT species. Total protein increased as drying increased but at 8% RWC decreased. All data of results are consistent with current views about studied factors and their roles during drying and induction of desiccation tolerance in DT plants.

Changes in some thylakoid membrane proteins and pigments upon desiccation of the resurrection plant Haberlea rhodopensis.

Science.gov (United States)

Georgieva, Katya; Röding, Anja; Büchel, Claudia

2009-09-15

The changes in some proteins involved in the light reactions of photosynthesis of the resurrection plant Haberlea rhodopensis were examined in connection with desiccation. Fully hydrated (control) and completely desiccated plants (relative water content (RWC) 6.5%) were used for thylakoid preparations. The chlorophyll (Chl) a to Chl b ratios of thylakoids isolated from control and desiccated leaves were very similar, which was also confirmed by measuring their absorption spectra. HPLC analysis revealed that beta-carotene content was only slightly enhanced in desiccated leaves compared with the control, but the zeaxanthin level was strongly increased. Desiccation of H. rhodopensis to an air-dried state at very low light irradiance led to a little decrease in the level of D1, D2, PsbS and PsaA/B proteins in thylakoids, but a relative increase in LHC polypeptides. To further elucidate whether the composition of the protein complexes of the thylakoid membranes had changed, we performed a separation of solubilized thylakoids on sucrose density gradients. In contrast to spinach, Haberlea thylakoids appeared to be much more resistant to the same solubilization procedure, i.e. complexes were not separated completely and complexes of higher density were found. However, the fractions analyzed provided clear evidence for a move of part of the antenna complexes from PSII to PSI when plants became desiccated. This move was also confirmed by low temperature emission spectra of thylakoids. Overall, the photosynthetic proteins remained comparatively stable in dried Haberlea leaves when plants were desiccated under conditions similar to their natural habitat. Low light during desiccation was enough to induce a rise in the xanthophyll zeaxanthin and beta-carotene. Together with the extensive leaf shrinkage and some leaf folding, increased zeaxanthin content and the observed shift in antenna proteins from PSII to PSI during desiccation of Haberlea contributed to the integrity of the

Desiccation stress induces developmental heterochrony in ...

Indian Academy of Sciences (India)

Stressful environments are known to perturb developmental patterns in insects. In the purview of desiccation as astressor, relatively little is known about the developmental consequences linked with desiccation tolerance. In thisstudy, we have particularly focused on the exploration of the temporal profile of postembryonic ...

A comparative study on the performance and environmental characteristics of R410A and R22 residential air conditioners

International Nuclear Information System (INIS)

Chen, W.

2008-01-01

R410A is a long-term alternative refrigerant with zero ODP (ozone-depleting-potential) for replacing R22. In this paper, four sets of comparable R410A and R22 split-type residential A/C (air conditioners) were developed and then their performance was comparatively studied using one simulation software. The A/C performance compared in this paper included the cooling capacity, EER (energy efficiency ratio), annual power consumption of A/C and the global warming impact of refrigerants adopted by the A/C. It was concluded that the adoption of R410A could be helpful for A/C to decrease their heat exchanger size or improve their operation efficiency for power saving. Moreover, compared to R22, R410A could in fact help alleviate its overall impact on global warming through significantly reducing the indirect global warming impact caused by operating R410A A/C

Parametric Analysis of Design Parameter Effects on the Performance of a Solar Desiccant Evaporative Cooling System in Brisbane, Australia

Directory of Open Access Journals (Sweden)

Yunlong Ma

2017-06-01

Full Text Available Solar desiccant cooling is widely considered as an attractive replacement for conventional vapor compression air conditioning systems because of its environmental friendliness and energy efficiency advantages. The system performance of solar desiccant cooling strongly depends on the input parameters associated with the system components, such as the solar collector, storage tank and backup heater, etc. In order to understand the implications of different design parameters on the system performance, this study has conducted a parametric analysis on the solar collector area, storage tank volume, and backup heater capacity of a solid solar desiccant cooling system for an office building in Brisbane, Australia climate. In addition, a parametric analysis on the outdoor air humidity ratio control set-point which triggers the operation of the desiccant wheel has also been investigated. The simulation results have shown that either increasing the storage tank volume or increasing solar collector area would result in both increased solar fraction (SF and system coefficient of performance (COP, while at the same time reduce the backup heater energy consumption. However, the storage tank volume is more sensitive to the system performance than the collector area. From the economic aspect, a storage capacity of 30 m3/576 m2 has the lowest life cycle cost (LCC of $405,954 for the solar subsystem. In addition, 100 kW backup heater capacity is preferable for the satisfaction of the design regeneration heating coil hot water inlet temperature set-point with relatively low backup heater energy consumption. Moreover, an outdoor air humidity ratio control set-point of 0.008 kgWater/kgDryAir is more reasonable, as it could both guarantee the indoor design conditions and achieve low backup heater energy consumption.

Subterranean termite open-air foraging and tolerance to desiccation: Comparative water relation of two sympatric Macrotermes spp. (Blattodea: Termitidae).

Science.gov (United States)

Hu, Jian; Neoh, Kok-Boon; Appel, Arthur G; Lee, Chow-Yang

2012-02-01

The foraging patterns of termites are strongly related to physiological limits in overcoming desiccation stress. In this study, we examined moisture preferences and physiological characteristics of Macrotermes carbonarius (Hagen) and M. gilvus (Hagen) as both exhibit conspicuous patterns of foraging activity. Despite both species showing no significant differences in calculated cuticular permeability, and percentage of total body water, they differed greatly in rate of water loss and surface area to volume ratio. For example, M. carbonarius which had a lower surface area to volume ratio (29.26-53.66) showed lower rate of water loss and percentage of total body water loss. This also resulted in higher LT(50) when exposed to extreme conditions (≈2% RH). However, contrasting observations were made in M. gilvus that has smaller size with higher surface area to volume ratio of 40.28-69.75. It is likely that the standard equation for calculating insect surface areas is inadequate for these termite species. The trend was further supported by the result of a moisture preference bioassay that indicated M. carbonarius had a broader range of moisture preference (between 5% and 20%) than M. gilvus which had a relatively narrow moisture preference (only 20%). These results explain why M. carbonarius can tolerate desiccation stress for a longer period foraging above-ground in the open air; while M. gilvus only forages below ground or concealed within foraging mud tubes. Copyright © 2011 Elsevier Inc. All rights reserved.

Computer Model to Estimate Reliability Engineering for Air Conditioning Systems

International Nuclear Information System (INIS)

Afrah Al-Bossly, A.; El-Berry, A.; El-Berry, A.

2012-01-01

Reliability engineering is used to predict the performance and optimize design and maintenance of air conditioning systems. Air conditioning systems are expose to a number of failures. The failures of an air conditioner such as turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply and loss of air flow entirely can be due to a variety of problems with one or more components of an air conditioner or air conditioning system. Forecasting for system failure rates are very important for maintenance. This paper focused on the reliability of the air conditioning systems. Statistical distributions that were commonly applied in reliability settings: the standard (2 parameter) Weibull and Gamma distributions. After distributions parameters had been estimated, reliability estimations and predictions were used for evaluations. To evaluate good operating condition in a building, the reliability of the air conditioning system that supplies conditioned air to the several The company's departments. This air conditioning system is divided into two, namely the main chilled water system and the ten air handling systems that serves the ten departments. In a chilled-water system the air conditioner cools water down to 40-45 degree F (4-7 degree C). The chilled water is distributed throughout the building in a piping system and connected to air condition cooling units wherever needed. Data analysis has been done with support a computer aided reliability software, this is due to the Weibull and Gamma distributions indicated that the reliability for the systems equal to 86.012% and 77.7% respectively. A comparison between the two important families of distribution functions, namely, the Weibull and Gamma families was studied. It was found that Weibull method performed for decision making.

The use of helical heat exchanger for heat recovery domestic water-cooled air-conditioners

International Nuclear Information System (INIS)

Yi Xiaowen; Lee, W.L.

2009-01-01

An experimental study on the performance of a domestic water-cooled air-conditioner (WAC) using tube-in-tube helical heat exchanger for preheating of domestic hot water was carried out. The main aims are to identify the comprehensive energy performance (space cooling and hot water preheating) of the WAC and the optimum design of the helical heat exchanger taking into account the variation in tap water flow rate. A split-type WAC was set up for experimental study at different indoor and outdoor conditions. The cooling output, the amount of recovered heat, and the power consumption for different hot water flow rates were measured. The experimental results showed that the cooling coefficient of performance (COP) of the WAC improves with the inclusion of the heat recovery option by a minimum of 12.3%. This can be further improved to 20.6% by an increase in tap water flow rate. Same result was observed for the comprehensive COP of the WAC. The maximum achievable comprehensive COP was 4.92 when the tap water flow rate was set at 7.7 L/min. The overall heat transfer coefficient of the helical heat exchanger under various operating conditions were determined by Wilson plot. A mathematical model relating the over all heat transfer coefficient to the outer pipe diameter was established which provides a convenient way of optimising the design of the helical heat exchanger

Proteomics of desiccation tolerance during development and germination of maize embryos

DEFF Research Database (Denmark)

Huang, Hui; Møller, Ian Max; Song, Song-Quan

2012-01-01

Maize seeds were used to identify the key embryo proteins involved in desiccation tolerance during development and germination. Immature maize embryos (28N) during development and mature embryos imbibed for 72 h (72HN) are desiccation sensitive. Mature maize embryos (52N) during development...... pattern. We infer that these eleven proteins are involved in seed desiccation tolerance. We conclude that desiccation-tolerant embryos make more economical use of their resources to accumulate protective molecules and antioxidant systems to deal with maturation drying and desiccation treatment........ are desiccation tolerant. Thiobarbituric acid reactive substance and hydrogen peroxide contents decreased and increased with acquisition and loss of desiccation tolerance, respectively. A total of 111 protein spots changed significantly (1.5 fold increase/decrease) in desiccation-tolerant and -sensitive embryos...

76 FR 18105 - Energy Conservation Program for Consumer Products: Test Procedures for Residential Central Air...

Science.gov (United States)

2011-04-01

... the lab-added transformer. Id. Under this proposal, the instrument used to measure the electrical... the low-voltage transformer used when testing coil-only residential central air conditioners and heat... the Low-Voltage Transformer Used When Testing Coil- Only Central Air Conditioners and Heat Pumps and...

Performance Optimization of Alternative Lower Global Warming Potential Refrigerants in Mini-Split Room Air Conditioners

Energy Technology Data Exchange (ETDEWEB)

Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Shrestha, Som S [ORNL

2017-01-01

Oak Ridge National laboratory (ORNL) recently conducted extensive laboratory, drop-in investigations for lower Global Warming Potential (GWP) refrigerants to replace R-22 and R-410A. ORNL studied propane, DR-3, ARM-20B, N-20B and R-444B as lower GWP refrigerant replacement for R-22 in a mini-split room air conditioner (RAC) originally designed for R-22; and, R-32, DR-55, ARM-71A, and L41-2, in a mini-split RAC designed for R-410A. We obtained laboratory testing results with very good energy balance and nominal measurement uncertainty. Drop-in studies are not enough to judge the overall performance of the alternative refrigerants since their thermodynamic and transport properties might favor different heat exchanger configurations, e.g. cross-flow, counter flow, etc. This study compares optimized performances of individual refrigerants using a physics-based system model tools. The DOE/ORNL Heat Pump Design Model (HPDM) was used to model the mini-split RACs by inputting detailed heat exchangers geometries, compressor displacement and efficiencies as well as other relevant system components. The RAC models were calibrated against the lab data for each individual refrigerant. The calibrated models were then used to conduct a design optimization for the cooling performance by varying the compressor displacement to match the required capacity, and changing the number of circuits, refrigerant flow direction, tube diameters, air flow rates in the condenser and evaporator at 100% and 50% cooling capacities. This paper compares the optimized performance results for all alternative refrigerants and highlights best candidates for R-22 and R-410A replacement.

Simulation Analysis of the Four Configurations of Solar Desiccant Cooling System Using Evaporative Cooling in Tropical Weather in Malaysia

Directory of Open Access Journals (Sweden)

M. M. S. Dezfouli

2014-01-01

Full Text Available A high demand for air conditioning systems exists in hot and humid regions because of the warm climate during the year. The high energy consumption of conventional air conditioning system is the reason for our investigation of the solar desiccant cooling system as an energy-efficient cooling system. Four model configurations were considered to determine the best configuration of a solar desiccant cooling system: one-stage ventilation, one-stage recirculation, two-stage ventilation, and two-stage recirculation. These models were stimulated for 8,760 hr of operation under hot and humid weather in Malaysia. Several parameters (i.e., coefficient of performance or COP, room temperature and humidity ratio, and the solar fraction of each system were evaluated by detecting the temperature and humidity ratio of the different points of each configuration by TRNSYS simulation. The latent and sensible loads of the test room were 0.875 kW and 2.625 kW, respectively. By investigating the simulation results of the four systems, the ventilation modes were found to be higher than the recirculation modes in the one- and two-stage solar desiccant cooling systems. The isothermal dehumidification COP of the two-stage ventilation was higher than that of the two-stage recirculation. Hence, the two-stage ventilation mode desiccant cooling system in a hot and humid area has higher efficiency than the other configurations.

Spectra of conditionalization and typicality in the multiverse

Science.gov (United States)

Azhar, Feraz

2016-02-01

An approach to testing theories describing a multiverse, that has gained interest of late, involves comparing theory-generated probability distributions over observables with their experimentally measured values. It is likely that such distributions, were we indeed able to calculate them unambiguously, will assign low probabilities to any such experimental measurements. An alternative to thereby rejecting these theories, is to conditionalize the distributions involved by restricting attention to domains of the multiverse in which we might arise. In order to elicit a crisp prediction, however, one needs to make a further assumption about how typical we are of the chosen domains. In this paper, we investigate interactions between the spectra of available assumptions regarding both conditionalization and typicality, and draw out the effects of these interactions in a concrete setting; namely, on predictions of the total number of species that contribute significantly to dark matter. In particular, for each conditionalization scheme studied, we analyze how correlations between densities of different dark matter species affect the prediction, and explicate the effects of assumptions regarding typicality. We find that the effects of correlations can depend on the conditionalization scheme, and that in each case atypicality can significantly change the prediction. In doing so, we demonstrate the existence of overlaps in the predictions of different "frameworks" consisting of conjunctions of theory, conditionalization scheme and typicality assumption. This conclusion highlights the acute challenges involved in using such tests to identify a preferred framework that aims to describe our observational situation in a multiverse.

Adhesive bonding of super-elastic titanium-nickel alloy castings with a phosphate metal conditioner and an acrylic adhesive.

Science.gov (United States)

Matsumura, H; Tanoue, N; Yanagida, H; Atsuta, M; Koike, M; Yoneyama, T

2003-06-01

The purpose of the current study was to evaluate the bonding characteristics of super-elastic titanium-nickel (Ti-Ni) alloy castings. Disk specimens were cast from a Ti-Ni alloy (Ti-50.85Ni mol%) using an arc centrifugal casting machine. High-purity titanium and nickel specimens were also prepared as experimental references. The specimens were air-abraded with alumina, and bonded with an adhesive resin (Super-Bond C & B). A metal conditioner containing a phosphate monomer (Cesead II Opaque Primer) was also used for priming the specimens. Post-thermocycling average bond strengths (MPa) of the primed groups were 41.5 for Ti-Ni, 30.4 for Ti and 19.5 for Ni, whereas those of the unprimed groups were 21.6 for Ti, 19.3 for Ti-Ni and 9.3 for Ni. Application of the phosphate conditioner elevated the bond strengths of all alloy/metals (P elastic Ti-Ni alloy castings can be achieved with a combination of a phosphate metal conditioner and a tri-n-butylborane-initiated adhesive resin.

Field test measurements and system optimisation at a solar operated DEC ventilation system at industrial use; Feldtest-Messungen und Systemoptimierung an einer solarbetriebenen DEC-Klimatisierungsanlage im industriellen Einsatz

Energy Technology Data Exchange (ETDEWEB)

Bader, Tobias; Finkenzeller, Michael; Trinkl, Christoph; Zoerner, Wilfried [Hochschule Ingolstadt (Germany). Kompetenzfeld Erneuerbare Energien

2010-07-01

The field of competence for renewable energy at the Ingolstadt University (Federal Republic of Germany) examines and optimizes an innovative, solar powered air conditioning system with DEC technology (DEC = Desiccant and Evaporative Cooling) in a multi-functional industrial buildings. In addition to a geothermal heat pump system for basic energy supply of heating and cooling, the building is fitted with two solar thermal solar collector panels and a sorption supported air conditioning system. This air conditioner consists of two units, each with a nominal air flow of 8,000 m{sup 3} per hour. The two solar collector panels provide the heat necessary for the regeneration of the sorption rotors and support the domestic preparation of hot water.

Chemical Risk Evaluation: A Case Study in an Automotive Air Conditioner Production Facility

Directory of Open Access Journals (Sweden)

Tengku Hanidza T.I.

2010-01-01

Full Text Available There has been limited knowledge on worker’s exposure to chemicals used in the automotive industries. The purpose of this study is to assess chemical risk and to determine the adequacy of the existing control measures to reduce chemical exposure. A cross sectional survey was conducted in a factory involving installation and servicing of automotive air conditioner units. Qualitative exposure assessment was carried out following the Malaysian Chemical Health Risk Assessment Manual (CHRA. There were 180 employees, 156 workers worked in the production line, which constitutes six work units Tube fin pressed, Brazing, Welding, Final assembly, Piping and Kit II. From the chemical risk evaluation for each work unit, 26 chemical compounds were used. Most of the chemicals were irritants (eye and skin and some were asphyxiants and sensitizers. Based on the work assignment, 93 out of 180 (51.67% of the workers were exposed to chemicals. The highest numbers of workers exposed to chemicals were from the Brazing section (22.22% while the Final Assembly section was the lowest (1.67%. Health survey among the workers showed occurrence of eye irritation, skin irritation, and respiratory irritation, symptoms usually associated with chemical exposure. Using a risk rating matrix, several work process were identified as having ‘significant risk’. For these areas, the workers are at risk of adverse health effects since chemical exposure is not adequately controlled. This study recommends corrective actions be taken in order to control the level of exposure and to provide a safe work environment for workers.

UPQC (Unified power Quality Conditioner)

Indian Academy of Sciences (India)

First page Back Continue Last page Graphics. UPQC (Unified power Quality Conditioner). Hybrid of Shunt and Series compensator. Compensate both Current Quality and Voltage Quality. Costlier Solution as it involves two set of Inverters.

Hospital-acquired infections associated with poor air quality in air-conditioned environments

Directory of Open Access Journals (Sweden)

Daniela Pinheiro da Silva

2013-10-01

Full Text Available Backgound and Objectives: Individuals living in cities increasingly spend more time indoors in air-conditioned environments. Air conditioner contamination can be caused by the presence of aerosols from the external or internal environment, which may be associated with disease manifestations in patients present in this type of environment. Therefore, the aim of this review was to assess the air quality in air-conditioned hospital environments as a risk factor for hospital-acquired infections – HAI – as the air can be a potential source of infection, as well as assess the exposure of professionals and patients to different pollutants. Material and Methods: A literature review was performed in the LILACS, MEDLINE, SCIELO, SCIENCE DIRECT databases, CAPES thesis database and Ministry of Health – Brazil, including studies published between 1982 and 2008. The literature search was grouped according to the thematic focus, as follows: ventilation, maintenance and cleaning of systems that comprehend the environmental quality standard. Discussion and Conclusion: Outbreaks of hospital-acquired infections associated with Aspergillus, Acinetobacter, Legionella, and other genera such as Clostridium and Nocardia, which were found in air conditioners, were observed, thus indicating the need for air-conditioning quality control in these environments.

Development of a novel rotary desiccant cooling cycle with isothermal dehumidification and regenerative evaporative cooling using thermodynamic analysis method

International Nuclear Information System (INIS)

La, D.; Li, Y.; Dai, Y.J.; Ge, T.S.; Wang, R.Z.

2012-01-01

A novel rotary desiccant cooling cycle is proposed and studied using thermodynamic analysis method. The proposed cycle integrates the technologies of isothermal dehumidification and regenerative evaporative cooling, which are beneficial for irreversibility reduction. Thermodynamic investigation on the basic rotary desiccant cooling cycle shows that the exergy efficiency of the basic cycle is only 8.6%. The processes of desiccant dehumidification and evaporative cooling, which are essentially the basis for rotary desiccant cooling, affect the exergy performance of the cycle greatly and account for about one third of the total exergy destruction. The proposed cycle has potential to improve rotary desiccant cooling technology. It is advantageous in terms of both heat source utilization rate and space cooling capacity. The exergy efficiency of the new cycle is enhanced significantly to 29.1%, which is about three times that of the ventilation cycle, and 60% higher than that of the two-stage rotary desiccant cooling cycle. Furthermore, the regeneration temperature is reduced from 80 °C to about 60 °C. The corresponding specific exergy of the supply air is increased by nearly 30% when compared with the conventional cycles. -- Highlights: ► A novel rotary desiccant cooling cycle is developed using thermodynamic analysis method. ► Isothermal dehumidification and regenerative evaporative cooling have been integrated. ► The cycle is advantageous in terms of both heat source utilization rate and space cooling capacity. ► Cascaded energy utilization is beneficial for cycle performance improvement. ► Upper limits, which will be helpful to practical design and optimization, are obtained.

Experimental study on air cleaning effect of clean air heat pump and its impact on ventilation requirement

DEFF Research Database (Denmark)

Fang, Lei; Sheng, Ying; Nie, Jinzhe

2017-01-01

This study investigated air purification effect of a Clean-Air Heat Pump (CAHP) which combined a desiccant wheel with a heat pump for both air cleaning and HVAC of buildings. The experiment was conducted in a field lab at four different outdoor air supply rates with and without air cleaning by CAHP....... Both sensory assessments of perceived air quality and chemical measurements of TVOC concentrations were conducted for evaluating the air cleaning performance of the CAHP. The results of experiment showed that running the CAHP improved significantly perceived air quality. At 2 L/s per person of outdoor...... air supply rate with operating the CAHP, the air quality was equivalent to the value at the higher outdoor air supply rate of 10 L/s per person without running CAHP. The TVOC measurements observed over 92% of efficiency on removal of indoor air VOCs and no VOCs accumulation on the desiccant wheel...

Unravelling desiccation tolerance in germinated Arabidopsis seeds

NARCIS (Netherlands)

Maia de Oliveira, J.

2014-01-01

How different organisms survive in the absence or under very limited amounts of water is still an open question. The aim of the research presented in this thesis is to explore the molecular basis of desiccation tolerance in seeds. We investigated the possibilities of using germinated desiccation

Desiccation tolerance of Sphagnum revisited: a puzzle resolved.

Science.gov (United States)

Hájek, T; Vicherová, E

2014-07-01

As ecosystem engineers, Sphagnum mosses control their surroundings through water retention, acidification and peat accumulation. Because water retention avoids desiccation, sphagna are generally intolerant to drought; however, the literature on Sphagnum desiccation tolerance (DT) provides puzzling results, indicating the inducible nature of their DT. To test this, various Sphagnum species and other mesic bryophytes were hardened to drought by (i) slow drying; (ii) ABA application and (iii) chilling or frost. DT tolerance was assessed as recovery of chlorophyll fluorescence parameters after severe desiccation. We monitored the seasonal course of DT in bog bryophytes. Under laboratory conditions, following initial de-hardening, untreated Sphagnum shoots lacked DT; however, DT was induced by all hardening treatments except chilling, notably by slow drying, and in Sphagnum species of the section Cuspidata. In the field, sphagna in hollows and lawns developed DT several times during the growing season, responding to reduced precipitation and a lowered water table. Hummock and aquatic species developed DT only in late autumn, probably as a response to frost. Sphagnum protonemata failed to develop DT; hence, desiccation may limit Sphagnum establishment in drier habitats with suitable substrate chemistry. Desiccation avoiders among sphagna form compact hummocks or live submerged; thus, they do not develop DT in the field, lacking the initial desiccation experience, which is frequent in hollow and lawn habitats. We confirmed the morpho-physiological trade-off: in contrast to typical hollow sphagna, hummock species invest more resources in water retention (desiccation avoidance), while they have a lower ability to develop physiological DT. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Stiffness of desiccating insect wings

International Nuclear Information System (INIS)

Mengesha, T E; Vallance, R R; Mittal, R

2011-01-01

The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 μN mm -1 h -1 . For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm -1 . (communication)

Stiffness of desiccating insect wings

Energy Technology Data Exchange (ETDEWEB)

Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: vallance@gwu.edu [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)

2011-03-15

The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process

Energy Technology Data Exchange (ETDEWEB)

Shin, Cheol Min; Qin, Hong Yi; Hong, Seok Jun; Jeon, Sang Hyuk; Kulkarni, Atul; Kim, Tae Sun [Sungkyunkwan University, Suwon (Korea, Republic of)

2016-12-15

During the Chemical mechanical planarization (CMP), the pad conditioning process can affect the pad surface characteristics. Among many CMP process parameters, the improper applied load on the conditioner arm may have adverse effects on the polyurethane pad. In this work, we evaluated the pad surface properties under the various conditioner arm applied during pad conditioning process. The conditioning pads were evaluated for surface topography, surface roughness parameters such as Rt and Rvk and Material removal rate (MRR) and within-wafer non-uniformity after wafer polishing. We observed that, the pad asperities were collapsed in the direction of conditioner rotation and blocks the pad pores applied conditioner load. The Rvk value and MRR were founded to be in relation with 4 > 1 > 7 kgF conditioner load. Hence, this study shows that, 4 kgF applied load by conditioner is most suitable for the pad conditioning during CMP.

Simulation and energy efficiency analysis of desiccant wheel systems for drying processes

International Nuclear Information System (INIS)

De Antonellis, Stefano; Joppolo, Cesare Maria; Molinaroli, Luca; Pasini, Alberto

2012-01-01

In drying processes it is necessary to appropriately control air humidity and temperature in order to enhance water evaporation from product surface. The aim of this work is to investigate several HVAC configurations for product drying based on desiccant wheels, in order to find systems which reach high primary energy savings through the appropriate integration of refrigerating machines, adsorption wheels and cogenerative engines. Simulations are carried out for different values of sensible to latent ambient load ratio and the effect of ambient and outside air conditions is evaluated for each configuration. It is shown that primary energy savings can reach 70–80% compared to the reference technology based on a cooling coil. With respect to works available in literature, the results of this study keep a general approach and they can be used as a simple tool for preliminary assessment in a wide range of applications. -- Highlights: ► Several HVAC systems for product drying based on desiccant wheels are investigated. ► The sensible to latent ambient load ratio influences the choice of the best system. ► Energy savings can reach 80% compared to the technology based on a cooling coil. ► Simulation results can be used for preliminary assessment in many applications.

In situ FTIR assessment of desiccation-tolerant tissues

NARCIS (Netherlands)

Wolkers, W.F.; Hoekstra, F.A.

2003-01-01

This essay shows how Fourier transform infrared (FTIR) microspectroscopy can be applied to study thermodynamic parameters and conformation of endogenous biomolecules in desiccation-tolerant biological tissues. Desiccation tolerance is the remarkable ability of some organisms to survive complete

Field Demonstration of Active Desiccant Modules Designed to Integrate with Standard Unitary Rooftop Package Equipment - Final Report: Phase 3

Energy Technology Data Exchange (ETDEWEB)

Fischer, J

2004-03-15

This report summarizes the investigation of two active desiccant module (ADM) pilot site installations initiated in 2001. Both pilot installations were retrofits at existing facilities served by conventional heating, ventilating, and air-conditioning (HVAC) systems that had encountered frequent humidity control, indoor air quality (IAQ), and other operational problems. Each installation involved combining a SEMCO, Inc., ADM (as described in Fischer and Sand 2002) with a standard packaged rooftop unit built by the Trane Company. A direct digital control (DDC) system integral to the ADM performed the dual function of controlling the ADM/rooftop combination and facilitating data collection, trending, and remote performance monitoring. The first installation involved providing preconditioned outdoor air to replace air exhausted from the large kitchen hood and bathrooms of a Hooters restaurant located in Rome, Georgia. This facility had previously added an additional rooftop unit in an attempt to achieve occupant comfort without success. The second involved conditioning the outdoor air delivered to each room of a wing of the Mountain Creek Inn at the Callaway Gardens resort. This hotel, designed in the ''motor lodge'' format with each room opening to the outdoors, is located in southwest Georgia. Controlling the space humidity always presented a serious challenge. Uncomfortable conditions and musty odors had caused many guests to request to move to other areas within the resort. This is the first field demonstration performed by Oak Ridge National Laboratory where significant energy savings, operating cost savings, and dramatically improved indoor environmental conditions can all be claimed as the results of a retrofit desiccant equipment field installation. The ADM/rooftop combination installed at the restaurant resulted in a reduction of about 34% in the electricity used by the building's air-conditioning system. This represents a reduction of

Modeling and experimental study on performance of inverter air conditioner with variation of capillary tube using R-22 and R-407C

International Nuclear Information System (INIS)

Sarntichartsak, Pongsakorn; Monyakul, Veerapol; Thepa, Sirichai

2007-01-01

This paper focuses on an investigation of the proper capillary tube length for an inverter air conditioner. Air to air variable capacity systems with R-22 and R-407C were tested and modeled. First, the optimum refrigerant charge was determined for four capillary tubes at full load condition by varying the mass charge from 1.1 kg to 1.9 kg. The capillary tube lengths were 1.016 m, 0.914 m, 0.813 m and 0.711 m. The two zone model, the distributed model and the combined model were compared to estimate the optimal charge inventory. The combined model analysed a simple path evaporator, a complex path condenser with a two zone model and a distributed model, respectively. It obtained good agreement with experimental results for the system performances and the optimum mass charge. Furthermore, four capillary tubes with specific optimum mass charges were investigated at compressor frequencies in a range of 30-50 Hz. The R-22 capillary tube obtains the best performance with the addition length of 1.016 m at the lowest frequency. Especially, the length of 0.813 m with R-407C is the appropriate size at the operation frequency of 30-35 Hz. The base capillary tube of 0.914 m is optimum at other frequencies. The model prediction agrees with the experimental data in a range of 40-50 Hz

Effects of natural and synthetic soil conditioners on soil moisture ...

African Journals Online (AJOL)

The efficacy of a natural soil conditioner, Coco-Peat (C-P), and synthetic soil conditioners, Terawet (T-200) and Teraflow (T-F), in improving soil moisture content were examined on five Ghanaian soil series (Akroso, Akuse, Amo, Hake and Oyarifa). In general, the water retention of T-200 and C-P treated soils were similar ...

Measurement of Vehicle Air Conditioning Pull-Down Period

Energy Technology Data Exchange (ETDEWEB)

Thomas, John F [ORNL; Huff, Shean P [ORNL; Moore, Larry G [ORNL; West, Brian H [ORNL

2016-08-01

Air conditioner usage was characterized for high heat-load summer conditions during short driving trips using a 2009 Ford Explorer and a 2009 Toyota Corolla. Vehicles were parked in the sun with windows closed to allow the cabin to become hot. Experiments were conducted by entering the instrumented vehicles in this heated condition and driving on-road with the windows up and the air conditioning set to maximum cooling, maximum fan speed and the air flow setting to recirculate cabin air rather than pull in outside humid air. The main purpose was to determine the length of time the air conditioner system would remain at or very near maximum cooling power under these severe-duty conditions. Because of the variable and somewhat uncontrolled nature of the experiments, they serve only to show that for short vehicle trips, air conditioning can remain near or at full cooling capacity for 10-minutes or significantly longer and the cabin may be uncomfortably warm during much of this time.

Numerically efficient simulation of multi-vaporator air conditioners in highly dynamic boundary conditions; Numerisch effiziente Simulation von Mehrverdampfer-Klimaanlagen unter hochdynamischen Randbedingungen

Energy Technology Data Exchange (ETDEWEB)

Schulze, Christian; Kaiser, Christian [TLK-Thermo GmbH, Braunschweig (Germany); Tegethoff, Wilhelm; Koehler, Juergen [TU Braunschweig (Germany). Inst. fuer Thermodynamik

2011-07-01

In the development of physically based models for dynamic simulations of cycle processes, a good equilibrium must be chosen between the degree of detailing and the speed of calculation. Dynamic modelling of mult-evaporator air conditioners is a special challenge as the interaction of several heat transfer fluides at one pressure level may result in numerically challenging effects like reflux. The contribution goes into the simulation of the heat transfer fluids in such systems in highly dynamic boundary conditions, e.g. after shutoff of the compressor. There are different modelling methods, e.g. finite volume, moving boundary, or finite element analysis. The methods are presented and evaluated. For the 1-D finite volume method, various established simplification strategies are presented that may enhance numerical efficiency. It is also shown that the equation system will not always be solvable with these strategies, and an approach to ensure solvability is presented. The new approach is illustrated by the example of a multi-evaporator bus air conditioner. [German] Bei der Erstellung von physikalisch basierten Modellen fuer die dynamische Simulation von Kreisprozessen muss ein gutes Gleichgewicht zwischen Detaillierungsgrad und Rechengeschwindigkeit gewaehlt werden: Das Modell muss die Realitaet hinreichend genau abbilden, im Gegenzug jedoch auch innerhalb eines angemessenen Zeitraums Ergebnisse liefern sowie in allen Betriebszustaenden loesbar sein. Die dynamische Modellierung von Mehrverdampfer-Klimaanlagen stellt im Vergleich zu einfachen Kreisprozessen eine besondere Herausforderung dar, da in diesen Systemen die Interaktion mehrerer Waermeuebertrager auf einem Druckniveau zu numerisch herausfordernden Effekten wie z. B. Rueckstroemung fuehren kann. Dieser Beitrag beschaeftigt sich mit der Simulation der Waermeuebertrager in diesen Systemen unter hochdynamischen Randbedingungen wie z. B. einer Abschaltung des Verdichters. Zur Modellierung der Waermeuebertrager

Study on effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans

Directory of Open Access Journals (Sweden)

Sari Farah Dina

2015-03-01

Full Text Available The main objective is to assess effectiveness of continuous solar dryer integrated with desiccant thermal storage for drying cocoa beans. Two type of desiccants were tested, molecular sieve 13× (Na86 [(AlO286·(SiO2106]·264H2O as an adsorbent type and CaCl2 as an absorbent type. The results revealed that during sunshine hours, the maximum temperature within the drying chamber varied from 40 °C to 54 °C. In average, it was 9–12 °C higher than ambient temperature. These temperatures are very suitable for drying cocoa beans. During off-sunshine hours, humidity of air inside the drying chamber was lower than ambient because of the desiccant thermal storage. Drying times for intermittent directs sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorbent were 55 h, 41 h, and 30 h, respectively. Specific energy consumptions for direct sun drying, solar dryer integrated with adsorbent, and solar dryer integrated with absorber were 60.4 MJ/kg moist, 18.94 MJ/kg moist, and 13.29 MJ/kg moist, respectively. The main conclusion can be drawn here is that a solar dryer integrated with desiccant thermal storage makes drying using solar energy more effective in term of drying time and specific energy consumption.

Effect of Nitrogen Starvation on Desiccation Tolerance of Arctic Microcoleus Strains (Cyanobacteria

Directory of Open Access Journals (Sweden)

Daria eTashyreva

2015-04-01

Full Text Available Although desiccation tolerance of Microcoleus species is a well-known phenomenon, there is very little information about their limits of desiccation tolerance in terms of cellular water content, the survival rate of their cells, and the environmental factors inducing their resistance to drying. We have discovered that three Microcoleus strains, isolated from terrestrial habitats of the High Arctic, survived extensive dehydration (to 0.23 g water g-1 dry mass, but did not tolerate complete desiccation (to 0.03 g water g-1 dry mass regardless of pre-desiccation treatments. However, these treatments were critical for the survival of incomplete desiccation: cultures grown under optimal conditions failed to survive even incomplete desiccation; a low temperature enabled only 0 to 15% of cells to survive, while 39.8 to 65.9% of cells remained alive and intact after nitrogen starvation. Unlike Nostoc, which co-exists with Microcoleus in Arctic terrestrial habitats, Microcoleus strains are not truly anhydrobiotic and do not possess constitutive desiccation tolerance. Instead, it seems that the survival strategy of Microcoleus in periodically dry habitats involves avoidance of complete desiccation, but tolerance to milder desiccation stress, which is induced by suboptimal conditions (e.g. nitrogen starvation.

Adsorption Machine & Desiccant Wheel based SOLAR COOLING in a Second Law perspective

OpenAIRE

Bivona, Santo

2011-01-01

This thesis work is intended to investigate energy and exergy performance of a low power prototype solar air conditioning system based on sorption materials. Its performance is analyzed in the light of both the First and Second Law of Thermodynamics and compared with conventional HVAC systems as well as with a further solar cooling technology based on desiccant wheels (Solar DEC). The adsorption machine based solar cooling plant was thoroughly designed and its thermal performance analysed ...

Reducing indoor air pollution by air conditioning is associated with improvements in cardiovascular health among the general population.

Science.gov (United States)

Lin, Lian-Yu; Chuang, Hsiao-Chi; Liu, I-Jung; Chen, Hua-Wei; Chuang, Kai-Jen

2013-10-01

Indoor air pollution is associated with cardiovascular effects, however, little is known about the effects of improving indoor air quality on cardiovascular health. The aim of this study was to explore whether improving indoor air quality through air conditioning can improve cardiovascular health in human subjects. We recruited a panel of 300 healthy subjects from Taipei, aged 20 and over, to participate in six home visits each, to measure a variety of cardiovascular endpoints, including high sensitivity-C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG), fibrinogen in plasma and heart rate variability (HRV). Indoor particles and total volatile organic compounds (VOCs) were measured simultaneously at the participant's home during each visit. Three exposure conditions were investigated in this study: participants were requested to keep their windows open during the first two visits, close their windows during the next two visits, and close the windows and turn on their air conditioners during the last two visits. We used linear mixed-effects models to associate the cardiovascular endpoints with individual indoor air pollutants. The results showed that increases in hs-CRP, 8-OHdG and fibrinogen, and decreases in HRV indices were associated with increased levels of indoor particles and total VOCs in single-pollutant and two-pollutant models. The effects of indoor particles and total VOCs on cardiovascular endpoints were greatest during visits with the windows open. During visits with the air conditioners turned on, no significant changes in cardiovascular endpoints were observed. In conclusion, indoor air pollution is associated with inflammation, oxidative stress, blood coagulation and autonomic dysfunction. Reductions in indoor air pollution and subsequent improvements in cardiovascular health can be achieved by closing windows and turning on air conditioners at home. Copyright © 2013 Elsevier B.V. All rights reserved.

Performance analysis of ventilation systems with desiccant wheel cooling based on exergy destruction

International Nuclear Information System (INIS)

Tu, Rang; Liu, Xiao-Hua; Hwang, Yunho; Ma, Fei

2016-01-01

Highlights: • Ventilation systems with desiccant wheel were analyzed from exergy destruction. • Main performances influencing factors for ventilation systems are put forward. • Improved ventilation systems with lower exergy destruction are suggested. • Performances of heat pumps driven ventilation systems are greatly increased. - Abstract: This paper investigates the performances of ventilation systems with desiccant wheel cooling from the perspective of exergy destructions. Based on the inherent influencing factors for exergy destructions of heat and mass transfer and heat sources, provide guidelines for efficient system design. First, performances of a basic ventilation system are simulated, which is operated at high regeneration temperature and low coefficient of performance (COP). Then, exergy analysis of the basic ventilation system shows that exergy destructions mainly exist in the heat and mass transfer components and the heat source. The inherent influencing factors for the heat and mass transfer exergy destruction are heat and mass transfer capacities, which are related to over dehumidification of the desiccant wheel, and unmatched coefficients, which represent the uniformity of the temperature or humidity ratio differences fields for heat and mass transfer components. Based on these findings, two improved ventilation systems are suggested. For the first system, over dehumidification is avoided and unmatched coefficients for each component are reduced. With lower heat and mass transfer exergy destructions and lower regeneration temperature, COP and exergy efficiency of the first system are increased compared with the basic ventilation system. For the second system, a heat pump, which recovers heat from the process air to heat the regeneration air, is adopted to replace the electrical heater and cooling devices. The exergy destruction of the heat pump is considerably reduced as compared with heat source exergy destruction of the basic ventilation

Experimental study on solar desiccant cooling system. 2nd Report; Taiyonetsu kudo desiccant cooling system no jikkenteki kento. 2

Energy Technology Data Exchange (ETDEWEB)

Tanaka, H; Funato, H [Fukuoka Institute of Technology, Fukuoka (Japan); Kuma, T [Seibu Giken Co. Ltd., Fukuoka (Japan)

1996-10-27

Study has been made about a desiccant cleaning system using solar heated water for regenerating the dehumidifier. A dehumidifier and evaporation coolers are combined to attain a synergistic effect in dehumidifying and cooling the air in the house. The simultaneous control of humidity and temperature, however, is quite difficult. Under the circumstances, an evaporation cooler was removed from the outdoor air intake side, to leave a humidifier alone for the control of humidity only. In addition, the length of the dehumidifier was reduced into half for saving fan driving power and for downscaling the model. With only one evaporation cooler in operation that is installed at the exhaust side, the cooling effect is diminished by half. For dealing with the situation, ultrasonic atomization is performed at the exhaust side evaporation cooler for the improvement of the air cooling effect for the next sensible heat exchanger (intake side). The return air is heated by the solar heater water (approximately 60{degree}C hot), regenerates the dehumidifier, and then exhausted. The atomization process elevates the cooling effect, and the resultant cooling effect was as high as that expected from a 2-cooler setup. The dehumidification effect, however, lowers a little. Exclusion of the atomization process will enhance the dehumidification effect, but will reduce the cooling effect as well. 3 refs., 8 figs., 3 tabs.

Power system stabilization by SMES using current-fed pwm power conditioner

International Nuclear Information System (INIS)

Ishikawa, T.; Akita, S.; Taniguchi, H.; Kosho, S.; Tanaka, T.

1988-01-01

A superconducting magnetic energy storage (SMES) unit, consisted of superconducting coil and AC/DC power conditioner, can be used to suppress various kinds of instability that may cause service interruption in electric power system as it has high controllability of input/output electric power. Power system stabilizing ability of SMES has been examined experimentally by using model power system and small SMES unit. Current-fed PWM power conditioner was used to obtain maximum stabilizing effect by controlling active and reactive power simultaneously and independently. Power conditioner configuration, operating characteristics and control scheme for power system stabilization are also described. Results from experiments show the effectiveness of SMES on power system stabilization

Inverted Unified Power Quality Conditioner to compensate overvoltage

Directory of Open Access Journals (Sweden)

Yeison Alberto Garcés Gómez

2017-07-01

Full Text Available Introduction: The use of unified power quality conditioners UPQC in the electric systems can correct waveform distortions in a steady state, like harmonics, flicker, and the power factor. Objective: This paper presents a novel approach for active compensation of overvoltage with a UPQC in dual topology or iUPQC. Methodology: The study it is presented in five stages, the section I shows an introduction and the state of the art, section II presents the unified power quality conditioner UPQC, section III describes the generalized reactive power theory applied to the iUPQC (dual topology, section IV shows the numerical simulations and the results and section V presents the conclusions of the study. Results: The results for the application of the iUPQC to the compensation of overvoltage are proved and compared with the more representative theory related to compensation of harmonics and low power factor. Conclusions: The control algorithm presented for the unified power quality conditioner in dual topology allows to compensate the overvoltage in three-phase systems as well as voltage and current harmonics and the low power factor.

PROSPECTS FOR THE DEVELOPMENT OF TECHNOLOGY AIR CONDITIONING

Directory of Open Access Journals (Sweden)

O. V. Chernyshova

2008-03-01

Full Text Available In the article the evaporation cooling and spray (aqueous and air-to-water types of the air-conditioning systems are considered, their merits and demerits are analyzed; the new scheme of a conditioner is offered.

LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

Science.gov (United States)

Ko, Suk M.

1980-01-01

This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

Desiccants for retrospective dosimetry using optically stimulated luminescence (OSL)

International Nuclear Information System (INIS)

Geber-Bergstrand, Therése; Bernhardsson, Christian; Christiansson, Maria; Mattsson, Sören; Rääf, Christopher L.

2015-01-01

Optically stimulated luminescence (OSL) was used to test different kinds of desiccants for their potential use in retrospective dosimetry. Desiccants are used for the purpose of absorbing liquids and can be found in a number of items which may be found in the immediate environment of a person, including hand bags, drug packages, and the vehicles of rescue service teams. Any material exhibiting OSL properties suitable for retrospective dosimetry is a useful addition to the existing dosimetry system available in emergency preparedness. Eleven kinds of desiccants were investigated in order to obtain an overview of the fundamental OSL properties necessary for retrospective dosimetry. Measurements were made using a Risø TL/OSL reader and irradiations were achieved with the 90 Sr/ 90 Y source incorporated in the reader. Several of the desiccants exhibited promising properties as retrospective dosemeters. Some of the materials exhibited a strong as-received signal, i.e. without any laboratory irradiation, but the origin of this signal has not yet been established. The minimum detectable dose ranged from 8 to 450 mGy for ten of the materials and for one material (consisting of natural clay) the minimum detectable dose was 1.8 Gy. - Highlights: • Desiccants can be used as fortuitous dosemeters using OSL. • The minimum detectable dose for processed desiccants range from 8 to 450 mGy. • The minimum detectable dose for natural clay was 1.8 Gy

Flow, stock, and impact assessment of refrigerants in the Japanese household air conditioner sector.

Science.gov (United States)

Xue, Mianqiang; Kojima, Naoya; Machimura, Takashi; Tokai, Akihiro

2017-05-15

Refrigerants provide society with great benefits while have the potential to cause adverse effects on the environment and human health. The present study estimated time-dependent flows and stocks and assessed the effects of refrigerants (R-22, R-410a, and R-32) in household air conditioners in Japan. It was found that stock of R-22 and R-410a peaked at 49,147t in 2000 and 55,994t in 2017, respectively. The largest flow of R-22 and R-410a to waste phase occurred at 3417t/yr. in 2005 and 4011t/yr. in 2023, respectively. The total global warming potential (GWP) due to refrigerant emissions increased from 3.6kt CO 2 eq. in 1952 to 6999kt CO 2 eq. in 2019, and then decreased to 5314kt CO 2 eq. in 2030. The ozone depletion potential (ODP) peaked at 141t CFC-11 eq. in 2002. When substituting R-410a for R-22, the ODP decreased 50% while the GDP increased 8%. When substituting R-32 for R-410a, there was no effect on the ODP while the GDP decreased 6%. The human health damage due to the global warming effect of refrigerant emission was much higher than that due to the ozone depleting effect. The refrigerant emission in use and waste management phases dominated the human health damage. The dynamic estimation not only allows us to evaluate the performance of past policies but also supports the future sustainable management associated with the health effects of refrigerants. Copyright © 2017 Elsevier B.V. All rights reserved.

Tolerance to environmental desiccation in moss sperm.

Science.gov (United States)

Shortlidge, Erin E; Rosenstiel, Todd N; Eppley, Sarah M

2012-05-01

• Sexual reproduction in mosses requires that sperm be released freely into the environment before finding and fertilizing a receptive female. After release from the male plant, moss sperm may experience a range of abiotic stresses; however, few data are available examining stress tolerance of moss sperm and whether there is genetic variation for stress tolerance in this important life stage. • Here, we investigated the effects of environmental desiccation and recovery on the sperm cells of three moss species (Bryum argenteum, Campylopus introflexus, and Ceratodon purpureus). • We found that a fraction of sperm cells were tolerant to environmental desiccation for extended periods (d) and that tolerance did not vary among species. We found that this tolerance occurs irrespective of ambient dehydration conditions, and that the addition of sucrose during dry-down improved cell recovery. Although we observed no interspecific variation, significant variation among individuals within species in sperm cell tolerance to environmental desiccation was observed, suggesting selection could potentially act on this basic reproductive trait. • The observation of desiccation-tolerant sperm in multiple moss species has important implications for understanding bryophyte reproduction, suggesting the presence of a significant, uncharacterized complexity in the ecology of moss mating systems. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

The system of thermoelectric air conditioning based on permeable thermoelements

Directory of Open Access Journals (Sweden)

Cherkez R. G.

2009-04-01

Full Text Available There is thermoelectric air conditioner unit on the basis of permeable cooling thermoelements presented. In thermoelectric air conditioner unit the thermoelectric effects and the Joule–Thomson effect have been used for the air stream cooling. There have been described the method of temperature distribution analysis, the determinations of energy conversion power characteristics and design style of permeable thermoelement with maximum coefficient of performance described. The results of computer analysis concerning the application of the thermoelement legs material on the basis of Bi2Te3 have shown the possibility of coefficient of performance increase by a factor of 1,6—1,7 as compared with conventional thermoelectric systems.

Production and exploitation of thermoelectric air conditioning systems for vehicles

Energy Technology Data Exchange (ETDEWEB)

Dudnik, Vladimir [Conditioner Ltd, Gagarin (Russian Federation); Skipidarov, Sergey [SCTB NORD, Moskau (Russian Federation); Rapp, Axel [Quick-Ohm Kupper und Co. GmbH, Wuppertal-Cronenberg (Germany)

2011-07-01

In the paper more than 10-year experience of thermoelectric devices batch manufacturing is described for the field of their obvious advantages. This field of application includes thermoelectric air conditioning systems which have shown their competitive advantage when used in vehicles of elevated vibration where compressor equipment application is difficult because of leakage of refrigerant. Energy characteristics of air conditioners for tractors, excavators, tanks, locomotive driver's cabins and cranes are described. Thermoelectric (TE) air conditioners mechanical test data as well as operation experience in vehicles are presented. It is shown that consumption of tellurium, which is a strategic component for thermoelectric materials manufacturing, may be lowered to 40 grams per 1 kW of cooling. (orig.)

Estimation of heat rejection based on the air conditioner use time and its mitigation from buildings in Taipei City

Energy Technology Data Exchange (ETDEWEB)

Hsieh, Chun-Ming; Aramaki, Toshiya; Hanaki, Keisuke [The University of Tokyo, Bunkyo-ku, Tokyo (Japan). Department of Urban Engineering

2007-09-15

The main work in the research focuses on the analysis and mitigation of the anthropogenic heat discharged from buildings, which is one of the main reasons leading to the heat island effect. The residential and commercial buildings, divided into 10 categories, with HVAC systems were analyzed by the building energy program, EnergyPlus. With the help of GIS, the heat rejection of all the residential and commercial buildings in DaAn Ward of Taipei City were evaluated, in which the spatial data and diurnal variation of the heat rejection were described by 3-h time periods. Furthermore, the effect of mitigation strategies was discussed. The first strategy was to change the wall/roof material of building envelope. The second and third strategies, from the viewpoint of energy saving, were to change the temperature setting of air conditioners and to turn off the lighting and equipment when not in use. The fourth strategy was to use a better efficiency of the cooling systems. Finally, the evaluation of installing the water-cooled cooling system, which discharges heat in the form of sensible and latent heat, was also included. (author)

Application of a diffusion model to measure ion leakage of resurrection plant leaves undergoing desiccation.

Science.gov (United States)

Mihailova, Gergana; Kocheva, Konstantina; Goltsev, Vasilij; Kalaji, Hazem M; Georgieva, Katya

2018-04-01

Haberlea rhodopensis is a chlorophyll-retaining resurrection plant, which can survive desiccation to air dry state under both low light and sunny environments. Maintaining the integrity of the membrane during dehydration of resurrection plants is extremely important. In the present study, the diffusion model was improved and used for a first time to evaluate the changes in ion leakage through different cellular compartments upon desiccation of H. rhodopensis and to clarify the reasons for significant increase of electrolyte leakage from dry leaves. The applied diffusion approach allowed us to distinguish the performance of plants subjected to dehydration and subsequent rehydration under different light intensities. Well-hydrated (control) shade plants had lower and slower electrolyte leakage compared to control sun plants as revealed by lower values of phase amplitudes, lower rate constants and ion concentration. In well-hydrated and moderately dehydrated plants (50% relative water content, RWC) ion efflux was mainly due to leakage from apoplast. The electrolyte leakage sharply increased in severely desiccated leaves (8% RWC) from both sun and shade plants mainly due to ion efflux from symplast. After 1 day of rehydration the electrolyte leakage was close to control values, indicating fast recovery of plants. We suggest that the enhanced leakage in air-dried leaves should not be considered as damage but rather as a survival mechanism based on a reversible modification in the structure of cell wall, plasma membrane and alterations in vacuolar system of the cells. However, further studies should be conducted to investigate the changes in cell wall/plasma membrane to support this conclusion. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Decontamination Using a Desiccant with Air Powder Abrasion Followed by Biphasic Calcium Sulfate Grafting: A New Treatment for Peri-Implantitis

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Giorgio Lombardo

2015-01-01

Full Text Available Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX, along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis.

Development of new products for Europe and individual customer support: Sanden Technical Centre (Europe) GmbH. High-efficiency wind tunnel for passenger car air conditioners at Bad Nauheim; Entwicklung neuer Produkte fuer Europa und individuelle Kundenunterstuetzung: Sanden Technical Centre (Europe) GmbH. Hocheffizienter Klimawindkanal fuer Pkw-Klimaanlagen in Bad Nauheim

Energy Technology Data Exchange (ETDEWEB)

Anon.

2007-05-15

As the importance of passenger cars as part of everyday life increased in Japan, Sanden decided that air conditioners for passenger cars would soon be indispensable. Since 1971, Sanden has worked on new technologies in this field, including compact refrigerating compressors. (orig.)

Desiccation tolerance in Anopheles coluzzii: the effects of spiracle size and cuticular hydrocarbons

Science.gov (United States)

Arcaz, Arthur C.; Huestis, Diana L.; Dao, Adama; Yaro, Alpha S.; Diallo, Moussa; Andersen, John; Blomquist, Gary J.; Lehmann, Tovi

2016-01-01

ABSTRACT The African malaria mosquitoes Anopheles gambiae and Anopheles coluzzii range over forests and arid areas, where they withstand dry spells and months-long dry seasons, suggesting variation in their desiccation tolerance. We subjected a laboratory colony (G3) and wild Sahelian mosquitoes during the rainy and dry seasons to desiccation assays. The thoracic spiracles and amount and composition of cuticular hydrocarbons (CHCs) of individual mosquitoes were measured to determine the effects of these traits on desiccation tolerance. The relative humidity of the assay, body water available, rate of water loss and water content at death accounted for 88% of the variation in desiccation tolerance. Spiracle size did not affect the rate of water loss or desiccation tolerance of the colony mosquitoes, as was the case for the total CHCs. However, six CHCs accounted for 71% of the variation in desiccation tolerance and three accounted for 72% of the variation in the rate of water loss. Wild A. coluzzii exhibited elevated desiccation tolerance during the dry season. During that time, relative thorax and spiracle sizes were smaller than during the rainy season. A smaller spiracle size appeared to increase A. coluzzii's desiccation tolerance, but was not statistically significant. Seasonal changes in CHC composition were detected in Sahelian A. coluzzii. Stepwise regression models suggested the effect of particular CHCs on desiccation tolerance. In conclusion, the combination of particular CHCs along with the total amount of CHCs is a primary mechanism conferring desiccation tolerance in A. coluzzii, while variation in spiracle size might be a secondary mechanism. PMID:27207644

Future air conditioning energy consumption in developing countries and what can be done about it: the potential of efficiency in the residential sector

Energy Technology Data Exchange (ETDEWEB)

McNeil, Michael A.; Letschert, Virginie E. [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory (United States)

2007-07-01

The dynamics of air conditioning are of particular interest to energy analysts, both because of the high energy consumption of this product, but also its disproportionate impact on peak load. This paper addresses the special role of this end use as a driver of residential electricity consumption in rapidly developing economies. Recent history has shown that air conditioner ownership grows more rapidly than economic growth in warm-climate countries. In 1990, less than a percent of urban Chinese households owned an air conditioner; by 2003 this number rose to 62 %. The evidence suggests a similar explosion of air conditioner use in many other countries is not far behind. Room air conditioner purchases in India are currently growing at 20 % per year, with about half of these purchases attributed to the residential sector. This paper draws on two distinct methodological elements to assess future residential air conditioner 'business as usual' electricity consumption by country/region and to consider specific alternative 'high efficiency' scenarios. The first component is an econometric ownership and use model based on household income, climate and demographic parameters. The second combines ownership forecasts and stock accounting with geographically specific efficiency scenarios within a unique analysis framework (BUENAS) developed by LBNL. The efficiency scenario module considers current efficiency baselines, available technologies, and achievable timelines for development of market transformation programs, such as minimum efficiency performance standards (MEPS) and labeling programs. The result is a detailed set of consumption and emissions scenarios for residential air conditioning.

Application of the CPE-air conditioner

Energy Technology Data Exchange (ETDEWEB)

Van Hest, J.; Van der Neut, R.P.; Wijnstra, K.P.

1986-09-01

Described is an air conditioning system with a special cooling unit, CPE (combined dew point and heat exchanger). The system has been installed for the first time in the Netherlands in a shop in Utrecht. Results of measurements during September 1985 are presented. 7 figs.

Sistema de enfriamiento con desecante para reducir consumo de energía en restaurante caso de estudio; Desiccant cooling system to decrease energy consumption in Restaurant study case

Directory of Open Access Journals (Sweden)

Tania Carbonell Morales

2015-12-01

Full Text Available Este artículo mostró la posibilidad de emplear un sistema de enfriamiento con rueda desecante para el tratamiento del aire de las diferentes áreas del Restaurante caso de estudio, instalación alta consumidora de energía, de ahí la necesidad de estudiar nuevas alternativas para el acondicionamiento de aire que permitan el control de la humedad y el ahorro de energía. El análisis bibliográfico realizado mostró que actualmente los sistemas de enfriamiento con desecante están siendo estudiados y empleados como una alternativa para el ahorro de energía y el cuidado del medioambiente en el campo del tratamiento del aire. Se propuso un sistema compuesto fundamentalmente por una rueda desecante de gel de sílice, una rueda conservadora de energía y un intercambiador de calor. Con el nuevo sistema de enfriamiento la demanda de energía eléctrica disminuye previéndose ahorros del orden de 1 1802 CUC anualmente solo por concepto de consumo de energía eléctrica.In this paper the possibility of using a cooling system with a desiccant wheel for air treatment of different areas of the case study restaurant is shown. This facility is classified as high consumer of energy, making it necessaryto study new alternatives for air conditioning allowing humidity control and energy saving. The literature review conducted on cooling systems with desiccant wheel technology was currently being studied and used as analternative to saving energy and protecting the environment in the field of air treatment. The desiccant cooling system proposed is fundamentally for a desiccant wheel of silica gel, an energy conservative wheel and a heatexchanger. With the new cooling system electricity demand decreases and significant savings of about 1 1802 CUC are forecasted only in annual electricity consumption.

Sistema de enfriamiento con desecante para reducir consumo de energía en restaurante caso de estudio; Desiccant cooling system to decrease energy consumption in Restaurant study case

Directory of Open Access Journals (Sweden)

Tania – Carbonell Morales

2016-02-01

Full Text Available Este artículo mostró la posibilidad de emplear un sistema de enfriamiento con rueda desecante para el tratamiento del aire de las diferentes áreas del Restaurante caso de estudio, instalación alta consumidora de energía, de ahí la necesidad de es tudiar nuevas alternativas para el acondicionamiento de aire que permitan el control de la humedad y el ahorro de energía. El análisis bibliográfico realizado mostró que actualmente los sistemas de enfriamiento con desecante están siendo estudia dos y empleados como una alternativa para el ahorro de energía y el cuidado del medioambiente en el campo del tratamiento del aire. Se propuso un sistema compuesto fundamentalmente por una rueda desecante de gel de sílice, una rueda conservadora de energía y un intercambiador de calor. Con el nuevo sistema de enfriamiento la demanda de energía eléctrica disminuye previéndose ahorros del orden de 11802 CUC anualmente solo por concepto de consumo de energía eléctrica. In this paper the possibility of using a cooling syst em with a desiccant wheel for air treatment of different areas of the case study restaurant is shown. This facility is classified as high consumer of energy, making it necessary to study new alternatives for air conditioning allowing humidity control and energy saving. The literature review conducted on cooling systems with desiccant wheel technology was currently being studied and used as an alternative to saving energy and protecting the environment in the field of air treatment. The desiccant cooling system proposed is fundamentally for a desiccant wheel of silica gel, an energy conservative wheel and a heat exchanger. With the new cooling system electricit y demand decreases and significant savings of about 11802 CUC are forecasted only in annual electricity consumption

Deep Vadose Zone Treatability Test for the Hanford Central Plateau: Interim Post-Desiccation Monitoring Results

Energy Technology Data Exchange (ETDEWEB)

Truex, Michael J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oostrom, Martinus [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Christian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Clayton, Ray E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chronister, Glen B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-09-01

A field test of desiccation is being conducted as an element of the deep vadose zone treatability test program. Desiccation technology relies on removal of water from a portion of the subsurface such that the resultant low moisture conditions inhibit downward movement of water and dissolved contaminants. Previously, a field test report (Truex et al. 2012a) was prepared describing the active desiccation portion of the test and initial post-desiccation monitoring data. Additional monitoring data have been collected at the field test site during the post-desiccation period and is reported herein along with interpretation with respect to desiccation performance. This is an interim report including about 2 years of post-desiccation monitoring data.

Review of Desiccant Dehumidification Technology

Energy Technology Data Exchange (ETDEWEB)

Pesaran, A. A.

1994-10-01

This paper overviews applications of desiccant technology for dehumidifying commercial and institutional buildings. Because of various market, policy, and regulatory factors, this technology is especially attractive for dehumidification applications in the I990s.

A Two-Level Optimal Scheduling Strategy for Central Air-Conditioners Based on Metal Model with Comprehensive State-Queueing Control Models

Directory of Open Access Journals (Sweden)

Yebai Qi

2017-12-01

Full Text Available Unlike some thermostatically controlled appliances (TCAs with small capacities, Central Air-conditioner (CAC has huge potential for demand response because of its large capacity. This paper presents a new CAC control strategy under multiple constraints. The CAC is modeled by three main modules: CAC central unit, water pumps, and temperature simulation of terminal users. The CAC’s power consumption is mainly determined by users’ load ratio. As the information and communication system have become the central nervous system of the smart grid, big data analysis is of great significance. Assuming that reliable two-way communication systems are preset, an integrated parameter priority list (IPPL control strategy is used to control and monitor CAC. A new intelligent algorithm, Space Exploration and Unimodal Region Elimination (SEUMRE algorithm, is introduced for solving the optimization problem of demand response targets generation under multiple constraints with the help of big data analysis. In this paper, influences and constrain factors, such as price and users’ comfortable levels are taken into account to satisfy the need of actual situation. Simulation results show that the proposed approach, when comparing with other typical optimization algorithms, yields better performances and efficiency.

Air Conditioner Charging. Automotive Mechanics. Air Conditioning. Instructor's Guide [and] Student Guide.

Science.gov (United States)

Spignesi, B.

This instructional package, one in a series of individualized instructional units on automobile air conditioning, consists of a student guide and an instructor guide dealing with air conditioning charging. Covered in the module are checking the air conditioning system for leaks, checking and adding refrigerant oil as needed, evacuating the system,…

Future emissions and atmospheric fate of HFC-1234yf from mobile air conditioners in Europe.

Science.gov (United States)

Henne, Stephan; Shallcross, Dudley E; Reimann, Stefan; Xiao, Ping; Brunner, Dominik; O'Doherty, Simon; Buchmann, Brigitte

2012-02-07

HFC-1234yf (2,3,3,3-tetrafluoropropene) is under discussion for replacing HFC-134a (1,1,1,2-tetrafluoroethane) as a cooling agent in mobile air conditioners (MACs) in the European vehicle fleet. Some HFC-1234yf will be released into the atmosphere, where it is almost completely transformed to the persistent trifluoroacetic acid (TFA). Future emissions of HFC-1234yf after a complete conversion of the European vehicle fleet were assessed. Taking current day leakage rates and predicted vehicle numbers for the year 2020 into account, European total HFC-1234yf emissions from MACs were predicted to range between 11.0 and 19.2 Gg yr(-1). Resulting TFA deposition rates and rainwater concentrations over Europe were assessed with two Lagrangian chemistry transport models. Mean European summer-time TFA mixing ratios of about 0.15 ppt (high emission scenario) will surpass previously measured levels in background air in Germany and Switzerland by more than a factor of 10. Mean deposition rates (wet + dry) of TFA were estimated to be 0.65-0.76 kg km(-2) yr(-1), with a maxium of ∼2.0 kg km(-2) yr(-1) occurring in Northern Italy. About 30-40% of the European HFC-1234yf emissions were deposited as TFA within Europe, while the remaining fraction was exported toward the Atlantic Ocean, Central Asia, Northern, and Tropical Africa. Largest annual mean TFA concentrations in rainwater were simulated over the Mediterranean and Northern Africa, reaching up to 2500 ng L(-1), while maxima over the continent of about 2000 ng L(-1) occurred in the Czech Republic and Southern Germany. These highest annual mean concentrations are at least 60 times lower than previously determined to be a safe level for the most sensitive aquatic life-forms. Rainwater concentrations during individual rain events would still be 1 order of magnitude lower than the no effect level. To verify these results future occasional sampling of TFA in the atmospheric environment should be considered. If future HFC-1234yf

LDDX: A High Efficiency Air Conditioner for DOD Buildings

Science.gov (United States)

2017-02-01

Additional Benefits ........................................................................................................ 3 1.2.6 Deliverables...inadequate latent cooling can lead building managers to restrict ventilation to minimal levels that further compromise both the comfort and health of...bulb temperatures for outdoor air and return air respectively per ANSI/AHRI Standard 210/240 “Performance Rating of Unitary Air-Conditioning and Air

An Experimental Evolution Test of the Relationship between Melanism and Desiccation Survival in Insects.

Directory of Open Access Journals (Sweden)

Subhash Rajpurohit

Full Text Available We used experimental evolution to test the 'melanism-desiccation' hypothesis, which proposes that dark cuticle in several Drosophila species is an adaptation for increased desiccation tolerance. We selected for dark and light body pigmentation in replicated populations of D. melanogaster and assayed several traits related to water balance. We also scored pigmentation and desiccation tolerance in populations selected for desiccation survival. Populations in both selection regimes showed large differences in the traits directly under selection. However, after over 40 generations of pigmentation selection, dark-selected populations were not more desiccation-tolerant than light-selected and control populations, nor did we find significant changes in mass or carbohydrate amounts that could affect desiccation resistance. Body pigmentation of desiccation-selected populations did not differ from control populations after over 140 generations of selection, although selected populations lost water less rapidly. Our results do not support an important role for melanization in Drosophila water balance.

The use of cooling systems with desiccants in the condition of buildings; El uso de sistemas de enfriamiento con desecantes en el acondicionamiento de edificaciones

Energy Technology Data Exchange (ETDEWEB)

Alpuche Cruz, Maria G; Avila Segura, Francisco [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico)

2000-07-01

In this document some papers about the development of solid and liquid desiccant cooling systems and dehumidification are analyzed. In a desiccant cooling cycle, the desiccant reduces the quantity of humidity of the air and temperature is decreases by others components such as heat exchangers, cooling evaporatives or conventional coolers. The main advantage of this systems is the capacity to use a low-grade thermal energy. These systems are being used in residence and commercial constructions to reduce energy and to optimize costs, however the initial cost is significantly higher that the conventional cooling systems. Recent studies have been focused in analyzing desiccant cooling systems, through computer modeling. [Spanish] En este documento se analizan algunas publicaciones sobre el desarrollo de los sistemas de enfriamiento y deshumidificacion con desecantes solidos y liquidos. En el ciclo de enfriamiento en el desecante, el desecante reduce la cantidad de humedad del aire y la temperatura se reduce por medio de otros componentes tales como intercambiadores de calor, enfriadores evaporativos o enfriadores convencionales. La ventaja principal que ofrecen estos sistemas es la capacidad de utilizar una baja cantidad de energia termica. Estos sistemas estan siendo utilizados en edificaciones habitacionales y comerciales para reducir el consumo de energia y optimizar costos, sin embargo el costo inicial es significativamente mas alto que los sistemas de enfriamiento convencionales. Estudios recientes se han enfocado en analizar estos sistemas de enfriamiento con desecantes, a traves de la modelacion por computadora.

Performance of a split-type air conditioner matched with coiled adiabatic capillary tubes using HCFC22 and HC290

International Nuclear Information System (INIS)

Zhou, Guobing; Zhang, Yufeng

2010-01-01

This paper experimentally investigated the system performance of a split-type air conditioner matching with different coiled adiabatic capillary tubes for HCFC22 and HC290. Experiments were carried out in a room-type calorimeter. The results have shown that (1) similar cooling effects can be achieved by matching various capillary tubes of different inner diameters; (2) parallel capillary tubes presented better system performance and flow stability with weaker inlet pressure fluctuations than the single capillary tube; (3) with the coil diameter of the capillary tube increasing from 40 mm to 120 mm, the mass flow rate tended to increase slightly. But the cooling capacity, input power and energy efficiency ratio (EER) did not show evident tendency of change; (4) the refrigerant charge and mass flow rate for HC290 were only 44% and 47% of that for HCFC22, respectively, due to the much lower density. And HC290 had 4.7-6.7% lower cooling capacity and 12.1-12.3% lower input power with respect to HCFC22. However, the EER of HC290 can be 8.5% higher than that of HCFC22, which exhibits the advantage of using HC290. In addition, the experimental uncertainties were analyzed and some application concerns of HC290 were discussed.

Identification of Novel Desiccation-Tolerant S. cerevisiae Strains for Deep Space Biosensors

Science.gov (United States)

Tieze, Sofia Massaro; Santa Maria, Sergio R.; Liddell, Lauren; Bhattacharya, Sharmila

2017-01-01

NASA's BioSentinel mission, a secondary payload that will fly on the Space Launch Systems first Exploration Mission (EM-1), utilizes the budding yeast S. cerevisiae to study the biological response to the deep space radiation environment. Yeast samples are desiccated prior to launch to suspend growth and metabolism while the spacecraft travels to its target heliocentric orbit beyond Low Earth Orbit. Each sample is then rehydrated at the desired time points to reactivate the cells. A major risk in this mission is the loss of cell viability that occurs in the recovery period following the desiccation and rehydration process. Cell survival is essential for the detection of the biological response to features in the deep space environment, including ionizing radiation.The aim of this study is to mitigate viable cell loss in future biosensors by identifying mutations and genes that confer tolerance to desiccation stress in rad51, a radiation-sensitive yeast strain. We initiated a screen for desiccation-tolerance after rehydrating cells that were desiccated for three years, and selected various clones exhibiting robust growth. To verify retention of radiation sensitivity in the isolated clonesa crucial feature for a successful biosensorwe exposed them to ionizing radiation. Finally, to elucidate the genetic and molecular bases for observed desiccation-tolerance, we will perform whole-genome sequencing of those rad51 clones that exhibit both robust growth and radiation sensitivity following desiccation. The identification and characterization of desiccation-tolerant strains will allow us to engineer a biological model that will be resilient in face of the challenges of the deep space environment, and will thus ensure the experimental success of future biosensor missions.

Factors influencing on the bioaccessibility of polybrominated diphenyl ethers in size-specific dust from air conditioner filters.

Science.gov (United States)

Yu, Yingxin; Yang, Dan; Wang, Xinxin; Huang, Ningbao; Zhang, Xinyu; Zhang, Dongping; Fu, Jiamo

2013-11-01

Size-specific concentrations and bioaccessibility of polybrominated diphenyl ethers (PBDEs) in dust from air conditioner filters were measured, and the factors influencing the PBDE bioaccessibility were determined. Generally, the PBDE concentrations increased with decreasing dust particle size, and BDE209 (deca-BDE) was generally the predominant congener. The bioaccessibility ranged from 20.3% to 50.8% for tri- to hepta-BDEs, and from 5.1% to 13.9% for BDE209 in dust fractions of varied particle size. The bioaccessibility of most PBDE congeners decreased with increasing dust particle size. The way of being of PBDE (adsorbed to dust surface or incorporated into polymers) in dust significantly influenced the bioaccessibility. There was a significant negative correlation between the tri- to hepta-BDE bioaccessibility and organic matter (OM) contents in dust. Furthermore, tri- to hepta-BDE bioaccessibility increased with increasing polarity of OMs, while with decreasing aromaticity of OMs. The tri- to hepta-BDE bioaccessibility significantly positively correlated with the surface areas and pore volumes of dust. Using multiple linear regression analysis, it was found that the OM contents and pore volumes of dust were the most important factors to influence the tri- to hepta-BDE bioaccessibility and they could be used to estimate the bioaccessibility of tri- to hepta-BDEs according to the following equation: bioaccessibility (%)=45.05-0.49 × OM%+1.79 × pore volume. However, BDE209 bioaccessibility did not correlate to any of these factors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Desiccation tolerance in bryophytes: The dehydration and rehydration transcriptomes in the desiccation-tolerant bryophyte Bryum argenteum.

Science.gov (United States)

Gao, Bei; Li, Xiaoshuang; Zhang, Daoyuan; Liang, Yuqing; Yang, Honglan; Chen, Moxian; Zhang, Yuanming; Zhang, Jianhua; Wood, Andrew J

2017-08-08

The desiccation tolerant bryophyte Bryum argenteum is an important component of desert biological soil crusts (BSCs) and is emerging as a model system for studying vegetative desiccation tolerance. Here we present and analyze the hydration-dehydration-rehydration transcriptomes in B. argenteum to establish a desiccation-tolerance transcriptomic atlas. B. argenteum gametophores representing five different hydration stages (hydrated (H0), dehydrated for 2 h (D2), 24 h (D24), then rehydrated for 2 h (R2) and 48 h (R48)), were sampled for transcriptome analyses. Illumina high throughput RNA-Seq technology was employed and generated more than 488.46 million reads. An in-house de novo transcriptome assembly optimization pipeline based on Trinity assembler was developed to obtain a reference Hydration-Dehydration-Rehydration (H-D-R) transcriptome comprising of 76,206 transcripts, with an N50 of 2,016 bp and average length of 1,222 bp. Comprehensive transcription factor (TF) annotation discovered 978 TFs in 62 families, among which 404 TFs within 40 families were differentially expressed upon dehydration-rehydration. Pfam term enrichment analysis revealed 172 protein families/domains were significantly associated with the H-D-R cycle and confirmed early rehydration (i.e. the R2 stage) as exhibiting the maximum stress-induced changes in gene expression.

Numerical study of the flow conditioner for the IFMIF liquid lithium target

Energy Technology Data Exchange (ETDEWEB)

Gordeev, S., E-mail: sergej.gordeev@kit.edu [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute for Thechnology, Campus North, Hermann v. Helmholtz Platz 1, D76344, Eggenstein-Leopoldshafen (Germany); Gröschel, F. [KIT Fusion Program, Karlsruhe Institute for Thechnology, Campus North, Hermann v. Helmholtz Platz 1, D76344, Eggenstein-Leopoldshafen (Germany); Heinzel, V.; Hering, W.; Stieglitz, R. [Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute for Thechnology, Campus North, Hermann v. Helmholtz Platz 1, D76344, Eggenstein-Leopoldshafen (Germany)

2014-10-15

Highlights: • A detailed numerical analysis of the flow conditioner efficiency has been performed. • The calculations show that the present design of the flow conditioner cannot suppress swirl motions emerging from the bend. • The transient simulation reveals flow instabilities between the separation zone and the accelerated outer region. • Calculation shows that pitched guide vanes upstream the elbow reduces a generation of backflow areas downstream. - Abstract: IFMIF (International Fusion Materials Irradiation Facility) is an accelerator-based deuteron–lithium (D–Li) neutron source to simulate the neutron irradiation field in a fusion reactor. The target assembly of the IFMIF consists of the flow conditioners and the nozzle, which has to form a stable lithium jet. This work focuses on a numerical study of the flow conditioner efficiency, in which two different types of flow conditioners are compared by means of a detailed numerical analysis with respect to specific hydraulic effects in the pipe elbow and the inflow conditioners. The adequateness of three different turbulence models to simulate a flow through a 90° bend of circular cross section has been examined. The calculations show that a honeycomb-screen combination is not capable to suppress effectively large scale swirl motions emerging from the bend. An increasing number of screens improves the flow uniformity downstream, but increases the pressure drop. In order to detect any transient effects in the separation area a flow straightener configuration consisting of a honeycomb with a subsequent screen has been analyzed by means of a detached eddy simulation (DES). A frequency analysis of the normalized static pressure amplitude conducted by means of a detached eddy simulation (DES) reveals instabilities in the shear layer between the separation zone and the accelerated outer region, which additionally increase the inhomogeneity of the axial velocity distribution. A set of six circumferentially

Antistranspirant compounds alleviate the mild-desiccation-induced reduction of vase life in cut roses

NARCIS (Netherlands)

Fanourakis, D.; Gebraegziabher, Habtamu; Li, Tao; Kambourakis, Emmanouil; Ligoxigakis, Eleftherios K.; Padadimitriou, Michael; Strataridaki, Argiro; Bouranis, Dimitrios; Fiorani, F.; Heuvelink, E.; Ottosen, Carl-Otto

2016-01-01

The vase life sensitivity to mild desiccation (12% weight loss) was addressed in rose, together with alleviation possibilities. The postharvest longevity upon arrival or following mild desiccation was determined on eight cultivars, combined with several morpho-physiological traits. Mild desiccation

De novo transcriptome characterization and gene expression profiling of the desiccation tolerant moss Bryum argenteum following rehydration.

Science.gov (United States)

Gao, Bei; Zhang, Daoyuan; Li, Xiaoshuang; Yang, Honglan; Zhang, Yuanming; Wood, Andrew J

2015-05-28

The desiccation-tolerant moss Bryum argenteum is an important component of the Biological Soil Crusts (BSCs) found in the Gurbantunggut desert. Desiccation tolerance is defined as the ability to revive from the air dried state. To elucidate the molecular mechanisms related to desiccation tolerance, we employed RNA-Seq and digital gene expression (DGE) technologies to study the genome-wide expression profiles of the dehydration and rehydration processes in this important desert plant. We applied a two-step approach to investigate the gene expression profile upon rehydration in the moss Bryum argenteum using Illumina HiSeq2000 sequencing platform. First, a total of 57,247 transcript assembly contigs (TACs) were obtained from 54.79 million reads by de novo assembly, with an average length of 863 bp and N50 of 1,372 bp. Among the reconstructed TACs, 36,916 (64.5%) revealed similarity with existing protein sequences in the public databases. 23,509 and 21,607 TACs were assigned GO and KEGG annotation information, respectively. Second, samples were taken from 3 hydration stages: desiccated (Dry), rehydrated 2 h (R2) and rehydrated 24 h (R24), and DEG libraries were constructed for Differentially Expressed Genes (DEGs) discovery. 4,081 and 6,709 DEGs were identified in R2 and R24, compared with Dry, respectively. Compared to the desiccated sample, up-regulated genes after two hours of hydration are primarily related to stress responses. GO function enrichment network, EKGG metabolic pathway and MapMan analysis supports the idea of the rapid recovery of photosynthesis after 24 h of rehydration. We identified 770 transcription factors (TFs) which were classified into 50 TF families. 142 TF transcripts were up-regulated upon rehydration including 23 members of the ERF family. In this study, we constructed a pioneering, high-quality reference transcriptome in B. argenteum and generated three DGE libraries to elucidate the changes of gene expression upon rehydration. Expression

Requirements of air conditioners for office buildings. Pt. 2

Energy Technology Data Exchange (ETDEWEB)

Radtke, W

1988-02-01

Presenting numerous explanatory diagrams part two of the report deals with auxiliary ventilation systems (mechanical systems); the influence of different ventilation circuits on the air quality (particle concentration, floor and ceiling air outlets); the requirements of heating systems (dimensioning of heating systems, effects of ventilation systems on the heat demand, reduced heat demand owing to auxiliary ventilation systems); the requirements of cooling (cooling loads in office buildings, room temperatures in the case of natural cooling, auxiliary ventilation systems, and cooling by means of refrigerators, floor/ceiling cooling systems); permissible ambient air velocities (complaints about draughts). Bottom-to-top ventilation circuits were found to provide for better air qualities and lower ambient air velocities without increasing the systems' energy demand. (HWJ).

Molecular strategies of the Caenorhabditis elegans dauer larva to survive extreme desiccation.

Directory of Open Access Journals (Sweden)

Cihan Erkut

Full Text Available Massive water loss is a serious challenge for terrestrial animals, which usually has fatal consequences. However, some organisms have developed means to survive this stress by entering an ametabolic state called anhydrobiosis. The molecular and cellular mechanisms underlying this phenomenon are poorly understood. We recently showed that Caenorhabditis elegans dauer larva, an arrested stage specialized for survival in adverse conditions, is resistant to severe desiccation. However, this requires a preconditioning step at a mild desiccative environment to prepare the organism for harsher desiccation conditions. A systems approach was used to identify factors that are activated during this preconditioning. Using microarray analysis, proteomics, and bioinformatics, genes, proteins, and biochemical pathways that are upregulated during this process were identified. These pathways were validated via reverse genetics by testing the desiccation tolerances of mutants. These data show that the desiccation response is activated by hygrosensation (sensing the desiccative environment via head neurons. This leads to elimination of reactive oxygen species and xenobiotics, expression of heat shock and intrinsically disordered proteins, polyamine utilization, and induction of fatty acid desaturation pathway. Remarkably, this response is specific and involves a small number of functional pathways, which represent the generic toolkit for anhydrobiosis in plants and animals.

The regeneration of a liquid desiccant using direct contact membrane distillation to unlock the potential of coastal desert agriculture

KAUST Repository

Cribbs, Kimberly

2018-04-01

In Gulf Cooperation Council (GCC) countries, a lack of freshwater, poor soil quality, and ambient temperatures unsuitable for cultivation for parts of the year hinders domestic agriculture. The result is a reliance on a fluctuating supply of imported fresh produce which may have high costs and compromised quality. There are agricultural technologies available such as hydroponics and controlled environment agriculture (CEA) that can allow GCC countries to overcome poor soil quality and ambient temperatures unsuitable for cultivation, respectively. Evaporative cooling is the most common form of cooling for CEA and requires a significant amount of water. In water-scarce regions, it is desirable for sea or brackish water to be used for evaporative cooling. Unfortunately, in many coastal desert regions, evaporative cooling does not provide enough cooling due to the high wet-bulb temperature of the ambient air during hot and humid months of the year. A liquid desiccant dehumidification system has been proven to lower the wet-bulb temperature of ambient air in the coastal city of Jeddah, Saudi Arabia to a level that allows for evaporative cooling to meet the needs of heat-sensitive crops. Much of the past research on the regeneration of the liquid desiccant solution has been on configurations that release water vapor back to the atmosphere. Studies have shown that the amount of water captured by the liquid desiccant when used to dehumidify a greenhouse can supply a significant amount of the water needed for irrigation. This thesis studied the regeneration of a magnesium chloride (MgCl2) liquid desiccant solution from approximately 20 to 31wt% by direct contact membrane distillation and explored the possibility of using the recovered water for irrigation. Two microporous hydrophobic PTFE membranes were experimentally tested and modeled when the bulk feed and coolant temperature difference was between 10 and 60°C. In eight experiments, the salt rejection was higher than 99

Preliminary report of a gas conditioner to improve operational reliability of cryotherapy in developing countries

Directory of Open Access Journals (Sweden)

Broekhuizen Fredrik

2006-02-01

Full Text Available Abstract Background Cryotherapy is a safe, affordable, and effective method of treatment for cervical intraepithelial neoplasia. In some low-resource settings, environmental conditions or qualities of the refrigerant gas can lead to blockage of cryotherapy equipment, terminating treatment. A prototype of a gas conditioner to prevent operational failure was designed, built, and field tested. Methods The prototype conditioner device consists of an expansion chamber that filters and dries the refrigerant gas. Users in Peru and Kenya reported on their experience with the prototype conditioner. In Ghana, simulated cryotherapy procedures were used to test the effects of the prototype conditioner, as well as the commonly used "cough technique." Results Anecdotal reports from field use of the device were favorable. During simulated cryotherapy, the prevalence of blockage during freezing were 0% (0/25 with the device alone, 23.3% (7/30 with the cough technique alone, 5.9% (1/17 with both, and 55.2% (16/29 with neither (Pearson's Chi square = 26.6, df = 3, p Conclusion This prototype design of a cryotherapy gas conditioner is a potential solution for low-resource settings that are experiencing cryotherapy device malfunction.

Characteristics of indoor radon and its progeny in a Japanese dwelling while using air appliances

International Nuclear Information System (INIS)

Pornnumpa, C.; Tokonami, S.; Sorimachi, A.; Kranrod, C.

2015-01-01

Characteristics of radon and its progeny were investigated in different air conditions by turning four types of indoor air appliances on and off in a two-story concrete Japanese dwelling. The four appliances were air conditioner, air cleaner, gas heater and cooker hood. The measurements were done using two devices: (1) a Si-based semiconductor detector for continuous measurement of indoor radon concentration and (2) a ZnS(Ag) scintillation counting system for equilibrium-equivalent radon concentration. Throughout the entire experiment, the cooker hood was the most effective in decreasing indoor radon concentration over a long period of time and the less effective was the air conditioner, while the air cleaner and gas heater did not affect the concentration of radon. However, the results measured in each air condition will differ according to the lifestyles and activities of the inhabitants. In this study, indoor radon and its progeny in a Japanese dwelling will be characterised by the different air conditions. (authors)

Model-based optimization strategy of chiller driven liquid desiccant dehumidifier with genetic algorithm

International Nuclear Information System (INIS)

Wang, Xinli; Cai, Wenjian; Lu, Jiangang; Sun, Youxian; Zhao, Lei

2015-01-01

This study presents a model-based optimization strategy for an actual chiller driven dehumidifier of liquid desiccant dehumidification system operating with lithium chloride solution. By analyzing the characteristics of the components, energy predictive models for the components in the dehumidifier are developed. To minimize the energy usage while maintaining the outlet air conditions at the pre-specified set-points, an optimization problem is formulated with an objective function, the constraints of mechanical limitations and components interactions. Model-based optimization strategy using genetic algorithm is proposed to obtain the optimal set-points for desiccant solution temperature and flow rate, to minimize the energy usage in the dehumidifier. Experimental studies on an actual system are carried out to compare energy consumption between the proposed optimization and the conventional strategies. The results demonstrate that energy consumption using the proposed optimization strategy can be reduced by 12.2% in the dehumidifier operation. - Highlights: • Present a model-based optimization strategy for energy saving in LDDS. • Energy predictive models for components in dehumidifier are developed. • The Optimization strategy are applied and tested in an actual LDDS. • Optimization strategy can achieve energy savings by 12% during operation

Surviving metabolic arrest: photosynthesis during desiccation and rehydration in resurrection plants.

Science.gov (United States)

Challabathula, Dinakar; Puthur, Jos T; Bartels, Dorothea

2016-02-01

Photosynthesis is the key process that is affected by dehydration in plants. Desiccation-tolerant resurrection plants can survive conditions of very low relative water content. During desiccation, photosynthesis is not operational, but is recovered within a short period after rehydration. While homoiochlorophyllous resurrection plants retain their photosynthetic apparatus during desiccation, poikilochlorophyllous resurrection species dismantle chloroplasts and degrade chlorophyll but resynthesize them again during rehydration. Dismantling the chloroplasts avoids the photooxidative stress in poikilochlorophyllous resurrection plants, whereas it is minimized in homoiochlorophyllous plants through the synthesis of antioxidant enzymes and protective proteins or metabolites. Although the cellular protection mechanisms in both of these species vary, these mechanisms protect cells from desiccation-induced damage and restore photosynthesis upon rehydration. Several of the proteins synthesized during dehydration are localized in chloroplasts and are believed to play major roles in the protection of photosynthetic structures and in recovery in resurrection species. This review focuses on the strategies of resurrection plants in terms of how they protect their photosynthetic apparatus from oxidative stress during desiccation without membrane damage and with full recovery during rehydration. We review the role of the dehydration-induced protection mechanisms in chloroplasts and how photosynthesis is restored during rehydration. © 2015 New York Academy of Sciences.

Key genes involved in desiccation tolerance and dormancy across life forms

NARCIS (Netherlands)

Costa, M.C.D.; Farrant, Jill M.; Oliver, Melvin J.; Ligterink, Wilco; Buitink, Julia; Hilhorst, H.M.W.

2016-01-01

Desiccation tolerance (DT, the ability of certain organisms to survive severe dehydration) was a key trait in the evolution of life in terrestrial environments. Likely, the development of desiccation-tolerant life forms was accompanied by the acquisition of dormancy or a dormancy-like stage as a

77 FR 23278 - Notice of Lodging of Consent Decree Under the Clean Air Act

Science.gov (United States)

2012-04-18

... accept small appliances, motor vehicle air conditioners (``MVACs''), or MVAC- like appliances with cut... DEPARTMENT OF JUSTICE Notice of Lodging of Consent Decree Under the Clean Air Act Notice is hereby... Agency (``U.S. EPA''), sought penalties and injunctive relief under the Clean Air Act (``CAA'') against...

Conceptual Design of Automotive Compressor for Integrated Portable Air Conditioning System

Directory of Open Access Journals (Sweden)

Ishak Muhammad Ikman

2017-01-01

Full Text Available This study introduces a new concept of portable air conditioner which integrated with some available components in automotive air conditioning system. This new idea intends to solve the storage problems as well as to reduce the price of current portable air conditioner since some devices could directly be used from the automotive air conditioning system. The primary emphasis of this study was on the modification of automotive compressor design so as the system may alternately be operated. The length of conventional compressor shaft is extended to place an additional clutch pulley, a drive plate and a clutch coil. The new concept particularly the shaft and pulley were analysed through slope deflection and computational finite element analyses. The result of engineering analyses exhibited that the new design of compressor shaft and clutch pulleys promote a low risk of failure as the data values recorded are lower than the critical value for each criterion investigated.

Fungal colonization of air-conditioning systems

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Ljaljević-Grbić Milica

2008-01-01

Full Text Available Fungi have been implicated as quantitatively the most important bioaerosol component of indoor air associated with contaminated air-conditioning systems. rarely, indoor fungi may cause human infections, but more commonly allergenic responses ranging from pneumonitis to asthma-like symptoms. From all air conditioner filters analyzed, 16 fungal taxa were isolated and identified. Aspergillus fumigatus causes more lethal infections worldwide than any other mold. Air-conditioning filters that adsorb moisture and volatile organics appear to provide suitable substrates for fungal colonization. It is important to stress that fungal colonization of air-conditioning systems should not be ignored, especially in hospital environments.

Campomanesia adamantium (Cambess.) O. Berg seed desiccation: influence on vigor and nucleic acids.

Science.gov (United States)

Dresch, Daiane M; Masetto, Tathiana E; Scalon, Silvana P Q

2015-01-01

The aim of this study was to evaluate the sensitivity of Campomanesia adamantium seeds to desiccation by drying in activated silica gel (fast) and under laboratory conditions (slow). To assess the sensitivity of the seeds to desiccation, we used drying with silica gel and drying under laboratory conditions (25 °C), in order to obtain seeds with moisture content of 45, 35, 30, 25, 20, 15, 10 and 5%. The physiological potential of the seeds after desiccation was evaluated by measuring primary root protrusion, percentage of normal seedlings, germination seed index, seedling length, total seedling dry mass, electrical conductivity and DNA and RNA integrities. The C. adamantium seeds were sensitive to desiccation and to a reduction in moisture content to 21.1% or less by desiccation using silica gel, and to 17.2% or less by desiccation under laboratory conditions; impairment of the physiological potential of the seeds was observed at these low moisture content levels. The integrity of the seed genomic DNA was not affected after drying seeds in the two methods. However, drying in silica gel to 4.5% moisture content and drying under laboratory conditions to 5.4% moisture content resulted in the loss of seed RNA integrity.

Campomanesia adamantium (Cambess. O. Berg seed desiccation: influence on vigor and nucleic acids

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DAIANE M. DRESCH

2015-12-01

Full Text Available The aim of this study was to evaluate the sensitivity of Campomanesia adamantium seeds to desiccation by drying in activated silica gel (fast and under laboratory conditions (slow. To assess the sensitivity of the seeds to desiccation, we used drying with silica gel and drying under laboratory conditions (25 °C, in order to obtain seeds with moisture content of 45, 35, 30, 25, 20, 15, 10 and 5%. The physiological potential of the seeds after desiccation was evaluated by measuring primary root protrusion, percentage of normal seedlings, germination seed index, seedling length, total seedling dry mass, electrical conductivity and DNA and RNA integrities. The C. adamantium seeds were sensitive to desiccation and to a reduction in moisture content to 21.1% or less by desiccation using silica gel, and to 17.2% or less by desiccation under laboratory conditions; impairment of the physiological potential of the seeds was observed at these low moisture content levels. The integrity of the seed genomic DNA was not affected after drying seeds in the two methods. However, drying in silica gel to 4.5% moisture content and drying under laboratory conditions to 5.4% moisture content resulted in the loss of seed RNA integrity.

The Signal Validation method of Digital Process Instrumentation System on signal conditioner for SMART

International Nuclear Information System (INIS)

Moon, Hee Gun; Park, Sang Min; Kim, Jung Seon; Shon, Chang Ho; Park, Heui Youn; Koo, In Soo

2005-01-01

The function of PIS(Process Instrumentation System) for SMART is to acquire the process data from sensor or transmitter. The PIS consists of signal conditioner, A/D converter, DSP(Digital Signal Process) and NIC(Network Interface Card). So, It is fully digital system after A/D converter. The PI cabinet and PDAS(Plant Data Acquisition System) in commercial plant is responsible for data acquisition of the sensor or transmitter include RTD, TC, level, flow, pressure and so on. The PDAS has the software that processes each sensor data and PI cabinet has the signal conditioner, which is need for maintenance and test. The signal conditioner has the potentiometer to adjust the span and zero for test and maintenance. The PIS of SMART also has the signal conditioner which has the span and zero adjust same as the commercial plant because the signal conditioner perform the signal condition for AD converter such as 0∼10Vdc. But, To adjust span and zero is manual test and calibration. So, This paper presents the method of signal validation and calibration, which is used by digital feature in SMART. There are I/E(current to voltage), R/E(resistor to voltage), F/E(frequency to voltage), V/V(voltage to voltage). Etc. In this paper show only the signal validation and calibration about I/E converter that convert level, pressure, flow such as 4∼20mA into signal for AD conversion such as 0∼10Vdc

Molecular mechanisms of desiccation tolerance in the resurrection glacial relic Haberlea rhodopensis

NARCIS (Netherlands)

Gechev, Tsanko S.; Benina, Maria; Obata, Toshihiro; Tohge, Takayuki; Sujeeth, Neerakkal; Minkov, Ivan; Hille, Jacques; Temanni, Mohamed-Ramzi; Marriott, Andrew S.; Bergstrom, Ed; Thomas-Oates, Jane; Antonio, Carla; Mueller-Roeber, Bernd; Schippers, Jos H. M.; Fernie, Alisdair R.; Toneva, Valentina

Haberlea rhodopensis is a resurrection plant with remarkable tolerance to desiccation. Haberlea exposed to drought stress, desiccation, and subsequent rehydration showed no signs of damage or severe oxidative stress compared to untreated control plants. Transcriptome analysis by next-generation

Desiccation resistance: effect of cuticular hydrocarbons and water content in Drosophila melanogaster adults

Directory of Open Access Journals (Sweden)

Jean-Francois Ferveur

2018-02-01

Full Text Available Background The insect cuticle covers the whole body and all appendages and has bi-directionnal selective permeability: it protects against environmental stress and pathogen infection and also helps to reduce water loss. The adult cuticle is often associated with a superficial layer of fatty acid-derived molecules such as waxes and long chain hydrocarbons that prevent rapid dehydration. The waterproofing properties of cuticular hydrocarbons (CHs depend on their chain length and desaturation number. Drosophila CH biosynthesis involves an enzymatic pathway including several elongase and desaturase enzymes. Methods The link between desiccation resistance and CH profile remains unclear, so we tested (1 experimentally selected desiccation-resistant lines, (2 transgenic flies with altered desaturase expression and (3 natural and laboratory-induced CH variants. We also explored the possible relationship between desiccation resistance, relative water content and fecundity in females. Results We found that increased desiccation resistance is linked with the increased proportion of desaturated CHs, but not with their total amount. Experimentally-induced desiccation resistance and CH variation both remained stable after many generations without selection. Conversely, flies with a higher water content and a lower proportion of desaturated CHs showed reduced desiccation resistance. This was also the case in flies with defective desaturase expression in the fat body. Discussion We conclude that rapidly acquired desiccation resistance, depending on both CH profile and water content, can remain stable without selection in a humid environment. These three phenotypes, which might be expected to show a simple relationship, turn out to have complex physiological and genetic links.

DISAIN SIMULATOR AUTOMOTIVE AIR CONDITIONING UNTUK MENINGKATKAN KOMPETENSI MAHASISWA

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Kamin Sumardi

2015-08-01

Full Text Available Perkembangan teknologi automotive air conditioning dan aplikasinya sangat cepat, salah satunya dengan menerapkan green technology. Penerapan green technology pada teknologi air conditioning, karena masih menggunakan refrigeran yang mengandung unsur kimia yang merusak lapisan ozon dan pemanasan global. Alih teknologi bidang air conditioning yang ramah lingkungan, belum dibarengi dengan ketersediaan tenaga kerja pada tingkat SMK dan perguruan tinggi yang memadai, baik kuantitas maupun kompetensinya. Pada level SMK dan perguruan tinggi, kompetensi akademik dan vokasional bidang automotive air conditioning harus terus ditingkatkan dan diperbaharui sesuai dengan perkembangan teknologinya. Penelitian ini bertujuan untuk menghasilkan simulator automotive air conditioner dan model pembelajaran tata udara pada otomotif berwawasan teknologi ramah lingkungan. Penelitian menggunakan metode research and development dengan langkah-langkah: studi pendahuluan, perencanaan, pengembangan melalui uji coba simulator, validasi, dan produk akhir. Simulator dibuat sesuai dengan kondisi di dunia kerja agar tidak terjadi miskonsepsi dan mala-praktek automotive air conditioning. Simulator ini dibuat secara kompak dan mobile atau dapat dipindah dan dibawa. Model pembelajaran disesuaikan dengan kebutuhan kompetensi yang dipersyaratkan. Hasil penelitian menunjukkan bahwa dengan bantuan simulator automotive air conditioner dan model pembelajaran yang tepat mahasiswa mampu menyerap konsep dan praktek lebih cepat 85%. Hasil belajar pada ranah afektif, kognitif, psikomotor dan kompetensi meningkat secara signifikan.

76 FR 76762 - Notice of Lodging of Consent Decree Under the Clean Air Act

Science.gov (United States)

2011-12-08

... recovery at no additional cost; (2) no longer accept small appliances, motor vehicle air conditioners... DEPARTMENT OF JUSTICE Notice of Lodging of Consent Decree Under the Clean Air Act Notice is hereby.... Environmental Protection Agency (``U.S. EPA''), sought penalties and injunctive relief under the Clean Air Act...

76 FR 57764 - Notice of Lodging of Consent Decree Under the Clean Air Act

Science.gov (United States)

2011-09-16

... recovery at no additional cost; (2) no longer accept small appliances, motor vehicle air conditioners... DEPARTMENT OF JUSTICE Notice of Lodging of Consent Decree Under the Clean Air Act Notice is hereby... Agency (``U.S. EPA''), sought penalties and injunctive relief under the Clean Air Act (``CAA'') against...

Pulmonary function tests in air conditioner users

African Journals Online (AJOL)

McRoy

2014-07-26

Jul 26, 2014 ... Background: Modernization has been implicated in the pathogenesis of allergic airway diseases. House dust, mites, and indoor air pollutants have been reported to cause elevation of serum IgE levels and/or enhancement of eosinophil activity. A component of modern lifestyle is the intense use of ...

Theoretical study for solar air pretreatment collector/regenerator

Energy Technology Data Exchange (ETDEWEB)

Peng Donggen; Zhang Xiaosong; Yin Yonggao [School of Energy and Environment, Southeast Univ., Nanjing (China)

2008-07-01

A new liquid regeneration equipment - solar air pretreatment collector/regenerator for liquid desiccant cooling system is put forward in this paper, which is preferable to solution regeneration in hot and moist climate in South China. The equipment can achieve liquid regeneration in lower temperature. When the solution and the air are in ''match'' state in collector/ regenerator, a match air to salt mass ratio ASMR* is found by theoretical study in which there is the largest theoretical storage capacity SC{sub max}. After two new concepts of the effective solution proportion (EPS) and the effective storage capacity (ESC) are defined, it is found by theoretical calculation that when ESP drops from 100% to 67%, ESC raises lowly, not drops and liquid outlet concentration C{sub str} {sub sol} increases from 40% to 49% in which its increment totals to 90%. All these data explain fully that air pretreatment liquid regeneration equipment enables to improve the performance of liquid desiccant cooling system. (orig.)

Concentrations of polybrominated diphenyl ethers (PBDEs) in central air-conditioner filter dust and relevance of non-dietary exposure in occupational indoor environments in Greece.

Science.gov (United States)

Besis, Athanasios; Katsoyiannis, Athanasios; Botsaropoulou, Elisavet; Samara, Constantini

2014-05-01

Polybrominated Diphenyl Ethers (PBDEs) are ubiquitous in the indoor environment owing to their use in consumer products and various studies around the world have found higher concentrations indoors than outdoors. Central air conditioner (A/C) systems have been widely used in many workplaces, therefore, studying of PBDEs in central A/C filter dust is useful to better understand the occurrences and health implications of PBDEs in indoor environments. The present study examined the occurrence of PBDEs in central A/C filter dust collected from various workplaces (n = 20) in Thessaloniki, Greece. The sum concentrations of 21 target congeners (∑21PBDE) in A/C dust ranged between 84 and 4062 ng g(-1) with a median value of 1092 ng g(-1), while BDE-209 was found to be the most abundant BDE congener. The daily intake via dust ingestion of PBDEs estimated for the employees of the occupational settings ranged from 3 to 45 ng day(-1) (median 12 ng day(-1)). Copyright © 2014 Elsevier Ltd. All rights reserved.

Freezing and desiccation tolerance in entomopathogenic nematodes: diversity and correlation of traits.

Science.gov (United States)

Shapiro-Ilan, David I; Brown, Ian; Lewis, Edwin E

2014-03-01

The ability of entomopathogenic nematodes to tolerate environmental stress such as desiccating or freezing conditions, can contribute significantly to biocontrol efficacy. Thus, in selecting which nematode to use in a particular biocontrol program, it is important to be able to predict which strain or species to use in target areas where environmental stress is expected. Our objectives were to (i) compare inter- and intraspecific variation in freeze and desiccation tolerance among a broad array of entomopathogenic nematodes, and (ii) determine if freeze and desiccation tolerance are correlated. In laboratory studies we compared nematodes at two levels of relative humidity (RH) (97% and 85%) and exposure periods (24 and 48 h), and nematodes were exposed to freezing temperatures (-2°C) for 6 or 24 h. To assess interspecific variation, we compared ten species including seven that are of current or recent commercial interest: Heterorhabditis bacteriophora (VS), H. floridensis, H. georgiana, (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All), S. feltiae (SN), S. glaseri (VS), S. rarum (17C&E), and S. riobrave (355). To assess intraspecific variation we compared five strains of H. bacteriophora (Baine, Fl1-1, Hb, Oswego, and VS) and four strains of S. carpocapsae (All, Cxrd, DD136, and Sal), and S. riobrave (355, 38b, 7-12, and TP). S. carpocapsae exhibited the highest level of desiccation tolerance among species followed by S. feltiae and S. rarum; the heterorhabditid species exhibited the least desiccation tolerance and S. riobrave and S. glaseri were intermediate. No intraspecific variation was observed in desiccation tolerance; S. carpocapsae strains showed higher tolerance than all H. bacteriophora or S. riobrave strains yet there was no difference detected within species. In interspecies comparisons, poor freeze tolerance was observed in H. indica, and S. glaseri, S. rarum, and S. riobrave whereas H. georgiana and S. feltiae exhibited the

Effect of Water Content Components on Desiccation and Recovery in Sphagnum Mosses

Science.gov (United States)

Hájek, Tomáš; Beckett, Richard P.

2008-01-01

Background and Aims The basic parameters of water relations were measured in Sphagnum mosses. The relationships of these parameters to the photosynthetic response to desiccation and the ecology of these mosses were then tested. Methods The water relations parameters of six Sphagnum species (mosses typical of wet habitats) and Atrichum androgynum (a moss more typical of mesophytic conditions) were calculated from pressure–volume isotherms. Photosynthetic properties during and after moderate desiccation were monitored by chlorophyll fluorescence. Key Results When desiccated, the hummock-forming species S. fuscum and S. magellanicum lost more water before turgor started dropping than other sphagna inhabiting less exposed habitats (73 % compared with 56 % on average). Osmotic potentials at full turgor were similar in all species, with an average value of −1·1 MPa. Hummock sphagna had clearly more rigid cell walls than species of wet habitats (ε = 3·55 compared with 1·93 MPa). As a result, their chlorophyllous cells lost turgor at higher relative water contents (RWCs) than species of wet habitats (0·61 compared with 0·46) and at less negative osmotic potentials (–2·28 compared with −3·00 MPa). During drying, ΦPSII started declining earlier in hummock species (at an RWC of 0·65 compared with 0·44), and Fv/Fm behaved similarly. Compared with other species, hummock sphagna desiccated to −20 or −40 MPa recovered more completely after rehydration. Atrichum androgynum responded to desiccation similarly to hummock sphagna, suggesting that their desiccation tolerance may have a similar physiological basis. Conclusions Assuming a fixed rate of desiccation, the higher water-holding capacities of hummock sphagna will allow them to continue metabolism for longer than other species. While this could be viewed as a form of ‘desiccation avoidance’, hummock species also recover faster than other species during rehydration, suggesting that they have higher