Energy Saving in a Heat Pump Air-Conditioning System Using Liquid Desiccant and Membrane Contactors

2011 ◽  
Author(s):  
Stefano Bergero ◽  
Anna Chiari
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Hybrid System ◽  
Air Conditioning ◽  
Energy Savings ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Membrane Contactor ◽  
Traditional System ◽  
Vapour Compression

It has been demonstrated in the literature that significant energy savings can be achieved in air-conditioning through the use of so-called hybrid systems, in which a chemical dehumidification system is combined with a vapour-compression heat pump. The advantage of such systems lies in the fact that the heat pump can operate at a higher evaporation temperature than that of a traditional system in which dehumidification is achieved through condensation, thereby achieving higher coefficients of performance. The hybrid system described in the present paper operates as follows: the air supplied to the conditioned ambient is simultaneously cooled and dehumidified in an air-solution membrane contactor. The LiCl solution is cooled by means of a vapour-compression heat pump using the refrigerant KLEA 410A. The solution is regenerated in another membrane contactor by exploiting the exhaust air and the heat rejected by the condenser. A study of the steady-state behaviour of the system in summer climatic conditions was carried out, on varying some significant operating parameters, such as the thermal efficiency of the heat exchangers, the outdoor temperature and the sensible load of the conditioned room. The performances of the hybrid system were compared with those of a traditional direct-expansion air-conditioning plant; the results of the simulations reveal that, in particular operating conditions, energy saving can exceed 50%.

Energy-Saving Characteristics of Benzene-Toluene Mixtures in Heat Pump Distillation Column

2012 ◽  
Vol 455-456 ◽  
pp. 630-634
Author(s):  
Zheng Ming Tong ◽  
Chao Li ◽  
Jia Lei Lu ◽  
Kai Zhu
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Distillation Column ◽  
Energy Savings ◽  
Operating Conditions ◽  
Material System ◽  
Industrial Energy ◽  
Energy Consuming ◽  
Benzene Toluene ◽  
Consuming Country

China is a big industrial energy consuming country. The largest proportion of energy consuming is the operations of separation in chemical industry, and the energy consumption of the distillation is the highest in separation. Therefore, it is very important to research energy-saving issues of the process of distillation in today's circumstances of the energy shortage. This article describes the model of heat pump distillation column,and its characteristics, uses static simulation programs to simulate operating conditions in the atmospheric pressure for the benzene-toluene material system, and studys effects of the different feed states on the energy-saving of heat pump distillation column. The results will be compared with the conventional distillation column, and it was showed that for benzene-toluene system, the heat pump distillation column is more remarkable than the conventional distillation column in energy savings, and its energy saving rate can reach 46%.

Study of Energy-Saving Characteristics of Propylene-Propane Mixtures in the Heat Pump Distillation Column

2011 ◽  
Vol 236-238 ◽  
pp. 1313-1316
Author(s):  
Zheng Ming Tong ◽  
Chao Li ◽  
Jia Lei Lu ◽  
Kai Zhu
Keyword(s):  
Energy Saving ◽  
Heat Pump ◽  
Distillation Column ◽  
Energy Savings ◽  
Operating Conditions ◽  
Material System ◽  
Saving Rate ◽  
Energy Consuming ◽  
Static Simulation ◽  
Energy Shortage

The largest proportion of energy consuming is the operations of separation in chemical industry, and the energy consumption of the distillation is the highest in separation. Therefore, it is very important to research energy-saving issues of the process of distillation in today's circumstances of the energy shortage. This article describes the model of the heat pump distillation column,and its characteristics, uses static simulation programs to simulate operating conditions in the same pressure for the propylene-propane material system, and studys effects of the different feed states on the energy-saving of heat pump distillation column. The results will be compared with the conventional distillation column, and it was showed that for propylene-propane system, the heat pump distillation column is more remarkable than the conventional distillation column in energy savings, and its energy saving rate can reach 56%.

Calculation on Energy Saving Potential of a New Dry-Type Air-Conditioning System

2013 ◽  
Vol 756-759 ◽  
pp. 4388-4393
Author(s):  
Xiao Wei Hu ◽  
Yu Feng Zhang ◽  
Li Li Wei ◽  
Xin Hui Wu
Keyword(s):  
Energy Efficiency ◽  
Energy Saving ◽  
Heat Pump ◽  
Air Conditioning ◽  
Type System ◽  
Operating Conditions ◽  
Combined System ◽  
Air Conditioning System ◽  
Efficiency Comparison ◽  
Conventional Cooling

Temperature and humidity independent control can be made by a new dry-type air-conditioning system, the combination of silica gel rotor and heat pump. Heat pump cycle can simultaneously cool the process air and heat the regeneration air, so it can cancel each other out in the cold and heat energy consumption within the system. This novel form of system not only solves the regeneration energy issues fundamentally but also avoids energy waste by reheating in conventional cooling dehumidification air-conditioning system. Based on the establishment of the component model, MATLAB program has been compiled to simulate the combined system running at nominal operating conditions and calculate the performance parameters and energy efficiency. Comparison of the energy efficiency was made of this dry-type air-conditioning system with ones of other regeneration desiccant wheel air conditioning system and conventional cooling dehumidification air-conditioning system, the results of which show that the new dry-type system provided regeneration energy, overcomes the restriction from climate, region and using conditions of other regeneration. Moreover, compared with conventional re-heat air-conditioning system, its energy saving is up to 35.1% and the energy efficiency is increased by 38.1%.

scholarly journals Investigation of Separated Two-Phase Thermosiphon Loop for Relieving the Air-Conditioning Loading in Datacenter

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 105 ◽  
Author(s):  
Hafiz Daraghmeh ◽  
Mohammed Sulaiman ◽  
Kai-Shing Yang ◽  
Chi-Chuan Wang
Keyword(s):  
Temperature Distribution ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Filling Ratio ◽  
Two Phase ◽  
System Pressure ◽  
Optimum Energy ◽  
Free Cooling ◽  
R 134A

This study investigates the feasibility of using R-134a filled separated two-phase thermosiphon loop (STPTL) as a free cooling technique in datacenters. Two data center racks one of them is attached with fin and tube thermosiphon were cooled by CRAC unit (computer room air conditioning unit) individually. Thermosiphon can help to partially eliminate the compressor loading of the CRAC; thus, energy saving potential of thermosiphon loop was investigated. The condenser is a water-cooled design and perfluoroalkoxy pipes were used as adiabatic riser/downcomer for easier installation and mobile capability. Tests were conducted with filling ratio ranging from 0 to 90%. The test results indicate that the energy saving increases with the rise of filling ratio and an optimum energy savings of 38.7% can be achieved at filling ratios of 70%, a further increase of filling ratio leads to a reduction in energy saving. At a low filling ratio like 10%, the evaporator starves for refrigerant and a very uneven air temperature distribution occurring at the exit of data rack. The uneven temperature distribution is relieved considerably when the evaporator is fully flooded. It is also found that the energy saving is in line with the rise of system pressure. Overfilling of the evaporator may lead to a decline of system pressure. A lower thermal resistance occurs at high filling ratios and higher ambient temperature.

scholarly journals An Optimal Hybrid Control Method for Energy-Saving of Chilled Water System in Central Air Conditioning

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Yan Zhang ◽  
Xiaoli Chu ◽  
Yongqiang Liu
Keyword(s):  
Energy Saving ◽  
Hybrid System ◽  
Air Conditioning ◽  
Control Method ◽  
System Modeling ◽  
Water System ◽  
Variable Frequency ◽  
Optimum Control ◽  
Central Air Conditioning ◽  
Frequency Behavior

Chilled water system of central air conditioning is a typical hybrid system; variable frequency behavior with amplitude limited of pumps reflects continuous and discrete dynamic characteristics. The way of energy-saving is variable water volume, via variable frequency behavior of pumps to gain adjustment of power consumption. Facing the situation of the variable frequency pumps with parallel operation, single continuous or discrete modeling cannot reflect the hybrid features. Thus, the control method will have some questions, such as bad energy-saving effect, difficult accurate adjustment of cold capacity, and low running energy efficiency. However, hybrid system modeling can reflect hybrid dynamic behavior of pumps, which is combining continuous and discrete features. The questions of nonlinear and multiparameters can be solved by control method based on hybrid system. Here, an optimum control method is proposed with the principle of the minimum, by setting the minimum power consumption as the performance function in fixed time, which realizes variable control of pumps and accurate adjustment of temperature inside room. At last, it shows the system characteristics and energy-saving affection by hybrid system modeling and the optimum control method.

Analysis for Energy Savings Potential and Economics of Combined Air-Conditioning System with Temperature and Humidity Decoupled Treatment

2011 ◽  
Vol 280 ◽  
pp. 71-75
Author(s):  
Zhong Chao Zhao ◽  
Dong Hui Zhang ◽  
Yu Ping Chen
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Air Conditioning ◽  
Energy Savings ◽  
Operating Cost ◽  
Air Conditioning System ◽  
Operation Mechanism ◽  
Energy Saving Potential ◽  
Temperature And Humidity

In this paper, the operation mechanism of combined air-conditioning system with temperature and humidity decoupled treatment (CACSTHDT) was presented, and the energy saving potential and economics of CACSTHDT were primarily analyzed through compared with a traditional air-conditioning system. The results indicated that CACSTHDT could save up to 28.64% energy consumption in comparison with a traditional air-conditioning system. The operating cost in one summer only was 71.36% of that cost of traditional air-conditioning system.

Vapour Compression and Liquid Desiccant Hybrid System for Air Conditioning

2006 ◽  
Author(s):  
Stefano Bergero ◽  
Anna Chiari ◽  
Enrico Nannei
Keyword(s):  
Air Conditioning ◽  
Power Saving ◽  
Operating Conditions ◽  
Dew Point ◽  
Operating Parameters ◽  
Direct Expansion ◽  
Liquid Desiccant ◽  
Hydrophobic Membrane ◽  
Air Conditioning System ◽  
Vapour Compression

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%.

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