scholarly journals Parametric analysis of a combined dew point evaporative-vapour compression based air conditioning system

2016 ◽  
Vol 55 (3) ◽  
pp. 2333-2344 ◽  
Author(s):  
Shailendra Singh Chauhan ◽  
S.P.S. Rajput
Author(s):  
Stefano Bergero ◽  
Anna Chiari ◽  
Enrico Nannei

The present study examines the performance of a hybrid air-conditioning system in which a vapour compression inverse cycle is integrated with an air dehumidification system working with hygroscopic solution and hydrophobic membrane. This approach may prove to be a valid alternative to the traditional summertime air-conditioning system, which involves cooling the air to below its dew point and subsequently reheating it. The system examined simultaneously cools and dehumidifies the air in an air-LiCl solution membrane vapour exchanger before it enters the conditioned environment. The LiCl solution is cooled by means of a vapour compression inverse cycle that uses the refrigerant KLEA 407C. The heat rejected by the condenser is used to regenerate the solution. A SIMULINK calculation programme was used to simulate the system in steady-state conditions. The performance of the system was analysed on varying significant operating parameters and was compared with that of a traditional direct-expansion air-conditioning plant. The results of the simulations revealed significant power saving which, in certain operating conditions, was as much as 50%.


2014 ◽  
Vol 628 ◽  
pp. 332-337
Author(s):  
Xiao Xia Xia ◽  
Nai Jun Zhou ◽  
Zhi Qi Wang

The energy consumption of several central air conditioning systems in summer was researched by the method of exergy analysis. Combined with actual example,the exergy loss of all the equipments and the exergy efficiency of three systems were calculated. The results show that the exergy efficiency of three systems is very low. Relatively speaking, the exergy efficiency of primary return air conditioning system with supplying air in dew point is highest. The equipment of highest exergy loss is air-conditioned room, while the exergy loss of surface air cooler is smallest. Based on this, several improvement measures were proposed to reduce exergy loss and improve exergy efficiency.


Author(s):  
J. P. Yadav ◽  
Bharat Raj Singh

The refrigeration units currently used in road transport vehicles are predominantly of the vapour compression refrigeration (VCR) type but this work represents study of air conditioning in automobile based on ammonia water vapour absorption system using hot exhaust gases as an energy source. In the study an experimental set up is designed and fabricated to use low grade heat energy i.e. exhaust gases as input heat to the system.


2020 ◽  
pp. 1420326X2096738
Author(s):  
Zan-She Wang ◽  
Fang-Ting Yin ◽  
Ran Li ◽  
Zhao-Lin Gu

The polyvinylidene fluoride hollow fibre membrane air dehumidification tests were carried out between the liquid desiccant solutions and the wet air. Three liquid desiccant solutions of LiBr solution (50%), LiCl solution (35%) and CaCl2 solution (40%) were tested under different wet air conditions. The results showed that all the membrane dehumidification processes were stable. The air moisture content in the outlet of the membrane was maintained as 6.5 g/kg (da)–8.2 g/kg (da) when the air moisture content in the inlet of the membrane was operated from 17.1 g/kg (da) to 32.4 g/kg (da). The dehumidification amount of LiBr solution (50%) and LiCl solution (35%) was more productive. On this basis, a membrane-based air pre-dehumidification process for the capillary radiant air conditioning system was built. Since the ideal dew point temperature range of the indoor air is below 14–17°C according to the cold supply water, all the air moisture content at the membrane outlet is much lower than that of the ideal dew point temperature range, which means non-condensing occurs in the capillary tube surface. The membrane-based air pre-dehumidification process can easily form an adaptive regulation process of humidity with the capillary radiant air conditioning system under different environmental parameters.


2013 ◽  
Vol 805-806 ◽  
pp. 125-130
Author(s):  
Xiu Wei Li ◽  
Xiao Song Zhang ◽  
Qing Cheng

Liquid dehumidification air-conditioning system is a promising air-conditioning system as it is environment-friendly, capable of utilizing low grade heat and less dependent on the electric power. However, because of the heat waste, its performance is not yet as competitive as vapour compression system. To improve, a photovoltaic driven system is proposed in this paper: electricity is applied to regenerate desiccant; the electric energy comes from solar power. Performance analysis has been made. The results show the coefficient of performance of the new system is influenced by the concentration of the desiccant and can approach 6 at certain circumstances. It also shows that LiBr solution is more favorable among three common used desiccants. Moreover, this paper presents the new progress of experimental research on this system.


2014 ◽  
Vol 670-671 ◽  
pp. 968-971
Author(s):  
Mao Ren Li

This project is mainly used in the comfort air conditioning system, replacing the conventional indoor air conditioning using fan convection cooling form, directly to the traditional air conditioning evaporator by convection heat transfer to type into the radiation heat transfer form, using modern new polymer composite material as the main body of the evaporator, the refrigerant cycle, in the mature theory of refrigeration the design of conventional air conditioning operating conditions of vapor compression on the overall setting of air conditioning design, exploration and design with the radiation air conditioning system technical requirements, the radiant cooling refrigerant system the data acquisition, development and design of intelligent controller and related problem of air conditioner indoor dew point control, thus the formation of completely based on the prototype structure of energy-saving radiation cooling technology of comfort air conditioning.


Author(s):  
Abdulghani A. Al-Farayedhi ◽  
Nasiru I. Ibrahim ◽  
P. Gandhidasan

Cooling load is the energy needed to be removed from a space by a cooling system to provide the desired level of comfort. Large space load requires high energy from the cooling system. A new technique of reducing the cooling load using condensate to pre-cool air stream entering the evaporator of a vapor compression air-conditioning system is presented in this paper. In a cooling process, water vapor condensation normally occurs when the evaporator coil surface temperature becomes lower than the dew point temperature of the humid air entering the evaporator. The cooling process results in appreciable amount of condensate in climatic conditions with high relative humidity and temperature such as those in Dhahran, Saudi Arabia. The rate of condensate yield is calculated using actual climate data of three typical summer days of Dhahran area for the months of June, July and August. These months are the most humid and hottest during the year. Each month is represented by a typical day determined by the average of the three hottest and humid days during the same months of the past three years. It is found that the condensate obtained during night time is more than the day time because of the high relative humidity at night. The results indicate that the cooling load can be reduced up to 10 % when the air entering the evaporator is pre-cooled by 4 °C using the condensate. In addition, the daily condensate yields from the evaporator coil in June, July and August are 1.27, 0.92 and 1.31 kg/kW-CDD, respectively.


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