Optimum selection of solar collectors for a solar-driven ejector air conditioning system by experimental and simulation study

2012 ◽  
Vol 63 ◽  
pp. 106-111 ◽  
Author(s):  
Wei Zhang ◽  
Xiaoli Ma ◽  
S.A. Omer ◽  
S.B. Riffat
2019 ◽  
Vol 95 (3) ◽  
pp. 296-301
Author(s):  
U. A. Rakhmanin ◽  
S. E. Shibanov ◽  
Sergey V. Kozulya

Purpose of work is a compilation of data about the microflora which colonizes a split-system, with the aim of selection of sanitary-indicative microorganisms, whose presence in the sample would indicate to the need for cleaning and disinfection of split-systems. Materials and methods. In the article there were used data of five years author’s scientific inquiry, related to the prevention of respiratory diseases, associated with the usage of a local air conditioning systems. We also use the data from the literature. Results. For selection of “indicative” microorganisms, we proposed the usage of nine criteria, each of them have numeric value from 0 to 3 points (risk for health, prevalence rate of the disease, epidemiological link, speed of split system’s colonization, difficulty of cultivation, resistance in the environment, resistance to disinfectants, frequency of detection in home air conditioning systems, frequency of detection in air conditioning systems of public buildings). After the calculation Pseudomonas aeruginosa and Staphylococcus aureus received maximal score (20 points). Therefore, these two types of bacteria are indicative microorganisms. The detection of these microorganisms in split systems will indicate to the contamination of air-conditioning system. This microflora also is a criterion of cleaning and disinfection quality - presence of these microorganisms in the samples after this process will mean that the processing of air conditioning systems was performed poorly. Conclusions. Split systems are very faster colonized by conditionally pathogenic and pathogenic microflora. To prevent the possible hazard for population’s health it is necessary to develop the normative base, according to which sanitary-and-hygienic control over the split-systems working must be carried out. Proposed criteria suggest that Pseudomonas aeruginosa and Staphylococcus aureus are indicative microorganisms, and it’s identification in the air-conditioning system would mean risk for health and necessity for cleaning and disinfection.


2013 ◽  
Vol 773 ◽  
pp. 883-888 ◽  
Author(s):  
Hamid Nawaz ◽  
Yan Sheng Yuan

The focus of this work is to simulate and optimize thermal comfort in a ship air-conditioning system by evaluating the performance of different types of air supply outlets. Thermal comfort analyses were performed in Solidworks Flow Simulation software by changing the number, type and position of air supply outlets and the comfort was optimized by evaluating the values of temperature, velocity, PMV (Predicted mean vote) & PPD (Predicted Percentage Dissatisfied). It was concluded from the results obtained from different analyses that air supply outlet is a vital part in any type of HVAC (Heating ventilation & air conditioning) system design, as its number, type and position has significant effect on the air distribution and thermal comfort in a subject space. It was also deduced that improper selection of air supply outlet can result in room air stagnation, unacceptable temperature gradients, and undesirable velocities in the occupied zone that may lead to occupant discomfort. Through this work the importance and effectiveness of CFD (computational fluid dynamics) design tools, in the design & optimization of HVAC systems has been evaluated and it was concluded that CFD design software like Solidworks flow simulation provide an excellent provision to validate different aspects of HVAC design before actual construction.


Solar Energy ◽  
2002 ◽  
Author(s):  
Jorge E. Gonza´lez ◽  
Luis Humberto Alva S.

This paper investigates the technical feasibility of using a compact, air-cooled, solar absorption air conditioning system when coupled to an innovative array of solar collectors. The particular absorption system of study is a single effect that uses lithium bromide and water as the absorbent and refrigerant fluid pair. The geographical location of interest is Puerto Rico and similar subtropical regions. The heat input to the absorption system generator is provided by an array of novels flat plate solar collectors that integrate the thermal storage component into them. The proposed collectors have a phase change material (PCM) integrated into them as a storage mechanism. The PCM-integrated solar collector eliminates the need of conventional storage tanks reducing cost and space. The present work uses a paraffin-graphite composite as the PCM to increase the conductivity of the PC matrix. The paraffin’s melting point is around 89°C that is appropriate for use in absorption systems. The mathematical model that describes the thermal process in the PCM is presented and differs from the analysis of conventional flat plate solar collectors. The proposed model for the PCM considers the temporal changes but not the spatial variations. The resulting set of equations for the fluid flow, the PCM, and the collector’s surface are solved simultaneously. Results for the collectors’ thermal performance are presented along with the effects of the composition of the PCM material. The thermal performance of an absorption machine coupled to an array of the proposed PCM’s solar collectors was investigated for nominal cooling capacities of 10.5, 14, and 17.5 kW. These cooling loads are suitable for a typical house or a small business building in Caribbean Islands. Computer simulations were conducted to evaluate the overall system’s performance when subjected to dynamic cooling loads. Within the computer model, heat and mass balances are conducted on each component of the system, including the solar collectors, the air-cooled condenser, and the air-cooled absorber. Comparisons are made with an absorption air conditioning system that uses a cooling tower with conventional flat plate collectors instead of air-cooled and PCM components. Useful information about physical dimensions of collectors, number of collectors needed, and efficiency of the overall system is presented.


Author(s):  
Ajay Landage

A simulation approach to heat pump systems is proposed in this paper. The evaluation of working fluids is conducted. Moreover, the selected refrigerants are used in the simulation. Subsequently, the system is analyzed in terms of the coefficient of performance (COP) and energy efficiency. Some alternative refrigerants, instead of R22 used R290 refrigerent. It is described the selection of refrigerants adapted to each utilization, based on the thermodynamic and -physical properties, the technological behaviour, costs and use constraints as principal aspects of the environmental protection. Also, it is performed a comparative analysis in function of the total equivalent warming impact (TEWI) for some possible substitutes of refrigerant R22 used in various refrigeration and heat pump systems.


Energy ◽  
2020 ◽  
Vol 210 ◽  
pp. 118521 ◽  
Author(s):  
Zongwei Han ◽  
Qiang Ji ◽  
Haotian Wei ◽  
Da Xue ◽  
Xiaoqing Sun ◽  
...  

2013 ◽  
Vol 732-733 ◽  
pp. 605-608
Author(s):  
Can Zhou ◽  
Yu Yun Li

Established a hierarchy structure model and made a quantitative assessment of seven air-conditioning systems which are gas boiler plus electric refrigerating system、air-cooled heat pump、variable refrigerant volume air conditioning、ground-source heat pump air conditioning、centralized heat-supply plus electric refrigerating、gas direct-fired machine、energy storage on relevant professionality and indoor environment,initial investment,operating costs,operation and management,environmental impact,energy consumption.Finally we obtained an optimal scheme,which agreed with that in practice.


2015 ◽  
Vol 89 ◽  
pp. 111-119 ◽  
Author(s):  
Xiu-Wei Li ◽  
Xiao-Song Zhang ◽  
Fang Wang ◽  
Xiao Zhao ◽  
Zhuo Zhang

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