Vapor Compression Air Conditioning Research Articles

An efficient low-grade thermal energy dual-driven elastocaloric cooling system: Thermodynamic cycle analysis, economic and sustainability assessment

Elastocaloric cooling is regarded as the most promising emerging refrigeration technology, with heat driven elastocaloric cycles at the forefront of research. However, existing systems often have actuators with a mass of 4–20 times that of the refrigerant, resulting in bulky structures and low thermodynamic efficiency. Enhancing system compactness and efficiency has thus become a critical research challenge. This study proposes an innovative low-grade thermal energy dual-driven elastocaloric cooling system, achieving a 1:1 mass ratio (mActuator/mRefrigerant) between the actuator and refrigerant, significantly improving system compactness and coefficient of performance while effectively reducing costs. A three-dimensional numerical and geometric model was developed to analyze the thermodynamic cycle, examining the effects of material, operational, and geometric parameters on cooling performance, and a “category-wise optimization” strategy was employed to determine optimal parameter combinations. The cost and environmental impacts of the new system were evaluated and compared with vapor-compression air conditioning. Results show that the difference in transformation temperatures between austenite and martensite phases significantly impacts cooling performance. Optimal flow rates and cycling frequencies are essential to avoid performance loss. Considering the coefficient of performance and heat transfer, a 1:1 mass ratio is optimal for geometric parameters. The system achieves a maximum coefficient of performance of 0.158, exceeding the existing two schemes by more than 2 times and 7 times, with a maximum temperature rise of 13.1 K. The proposed system is economically feasible and environmentally friendly, providing valuable theoretical foundations and technical solutions for developing sustainable alternative refrigeration technologies.

Impact of Air Conditioning Type on Outdoor Ozone Intrusion into Homes in a Semi-Arid Climate

Outdoor ozone (O3) is elevated on hot, sunny days when residential air conditioning is used most. We evaluated the impact of direct evaporative coolers (ECs) and vapor-compression air conditioners (ACs) on indoor O3 concentrations in homes (N = 31) in Utah County, Utah, United States of America. Indoor and outdoor O3 concentrations were measured for 24 h at each home using nitrite-impregnated glass-fiber filters. AC homes (n = 16) provided a protective envelope from outdoor O3 pollution. Only one AC home had O3 levels above the limit of detection (LOD). Conversely, EC homes (n = 15) provided minimal protection from outdoor O3. Only one EC home had O3 levels below the LOD. The average indoor O3 concentration in EC homes was 23 ppb (95% CI 20, 25). The indoor-to-outdoor (I/O) ratio for O3 in EC homes was 0.65 (95% CI 0.58, 0.72), while the upper bound for the I/O ratio for AC homes was 0.13 (p < 0.001). Indoor exposure to O3 for residents in EC homes is approximately five times greater than for residents of AC homes. Although ECs offer energy and cost-saving advantages, public health awareness campaigns in O3-prone areas are needed, as well as research into O3 pollution controls for direct ECs such as activated carbon filtration.

Performance study on a hybrid solid desiccant‐vapor compression air‐conditioning system for hot‐humid ambient conditions

AbstractThe paper focuses on the simulation and testing of a hybrid solid desiccant‐vapor compression air‐conditioning system under different hot‐humid climates. The simulation is carried out by a BLUEJ programming framework. Air at the lowest achievable temperatures from a solid desiccant cooling system is supplied to a standard vapor compression air‐conditioning system (VCAS). The cooling capacities of the hybrid system under three modes 1, 2, and 3, indicating different supply air conditions to the cabin, are reported in the paper. This paper expresses the trade‐off between having comfort conditions and reasonable comfort conditions inside the cooling space with energy efficiency as the inflection point. The more the study is moved towards the point of energy efficiency, the higher the reduction in the cooling capacities of the vapor compression air conditioner. This is demonstrated by the cooling capacity savings when the system is operated in three modes namely 1, 2, and 3. The substantial energy savings provided by Mode 1, Mode 2, and Mode 3 are 71%, 57%, and 37%, respectively. If the system is made to provide substantial cooling and focuses deeply on cooling capacity savings, then the system could save up to 77% in the cooling capacity of the vapor compression air‐conditioning system. If the system is made to operate solely with the milestone of comfort cooling for the occupants with any substantial savings in the cooling capacity of the vapor compression air‐conditioning system, then Mode 3 would deliver the milestone and give savings in the cooling capacities from 32% to 41% which is a significant savings. From the results of the performance study, it is inferred that the hybrid system provides significant energy savings compared to a standard air conditioner, especially in hot‐humid ambient conditions. The solid desiccant cooling system thus establishes itself as an effective pre‐cooler unit for a VCAS. The hybrid solid desiccant air‐conditioning in the paper is analyzed from the aspects of savings in cooling capacities of an existing vapor compression air‐conditioning system and comfort cooling. This is a newer operational approach, especially for using this hybrid solid desiccant cooling system for ambient humidity ratios greater than 15 kg−1 d.a.

Thermodynamic performance assessment of a solar-driven desiccant evaporative air cooling system (SDEAC) for outdoor environments- a dynamic study

In this work, a novel dynamic model of a solar-driven desiccant evaporative air cooling system for outdoor environments is proposed, namely the SDEAC system. The effects of operating and designing parameters on the performance of the SDEAC system are analyzed. The results indicate that the sensible cooling capacity, the latent cooling capacity, and the COP decrease monotonically as the rotational speed of the desiccant wheel increases. When the ratio of dehumidification area to total area (r1) is 0.5, the performance of the SDEAC system is optimal under the condition of sufficient solar radiation. The ratio of the dehumidified air flowrate to the regenerated air flowrate has a small effect on the cooling capacity but has a large effect on the COP. The SDEAC system has a higher sensible cooling capacity and total cooling capacity compared to the EAC system. Moreover, although the COP of the SDEAC is lower than that of the EAC system, it is still maintained at a relatively high level. The SDEAC system with a supply air flowrate of 670 m3/h to cool the outdoor air saves about 1283∼1617 kWh of electricity and 788 kg–1139 kg of carbon emission reduction compared to a conventional vapor compression air conditioning system in different cities during the period of June to August.

Effect of polyvinylpyrrolidone and lithium chloride composite desiccant-coated heat exchangers on dehumidification studies

Cooling systems are necessities that remain energy intensive, particularly in tropical regions with elevated humidities and temperatures. Conventional vapor-compression air-conditioners are often inefficient because the sensible and latent heat loads are intrinsically coupled. To realize more energy-efficient cooling, solid desiccant-coated devices can be introduced to mitigate the latent heat load. Among such devices, desiccant-coated heat exchangers (DCHEs) are attractive for enabling nearly isothermal dehumidification. Hence, desiccants with high sorption capacity and rapid kinetics are essential. Solid polymeric desiccants are well-positioned to meet these requirements but comprehensive studies on the dehumidification performance of solid polymeric desiccant-coated heat exchangers are currently lacking. In this study, we investigated the potential of polyvinylpyrrolidone (PVP) and lithium chloride (LiCl) composites as desiccant materials at both material and system levels in terms of gravimetric water uptake. Specifically, LiCl is a hygroscopic salt bound by the moisture-sorbing PVP matrix. This work also demonstrates how the Elovich model accurately predicted the PVP-LiCl composite’s sorption kinetics. The results show that the optimum PVP-LiCl composite ratio is 66.7 wt%, with an equilibrium sorption capacity of 280 % at 75 % RH and 25 °C, compared to 29 % for silica gel under the same condition. With much superior sorption kinetics and capacity, the PVP-LiCl-coated prototype heat exchanger demonstrated a moisture removal capacity eight times higher than a silica gel-coated one under dynamic flow towards energy savings in air-conditioning systems.

Impact of Ambient Temperature and Humidity on the Performance of Vapour Compression Air Conditioning System - Experimental and Numerical Investigation

Due to global warming, population growth, and urbanisation, demands for space cooling in buildings have significantly increased. Mechanical vapour compression cooling technology is relatively mature, well-understood and most commonly used globally. However, they suffer from high energy consumption and adverse environmental impact due to the refrigerants used. As ambient temperature and humidity have significant effects on the performance of vapour compression systems, this paper experimentally and numerically investigates their impact on the performance of vapour compression air conditioning system in terms of power consumption and cooling capacity. It was concluded that at ambient humidity of 55%, as the ambient temperature increases from 22 °C to 40 °C, the compressor temperature has increased from 46 °C to 59 °C which increased its power consumption from 751.2 to 935.52 Watts, giving an increase of 10.24 Watts for every one degree of ambient temperature increase. Also, as ambient humidity in-creased from 32% to 88%, the power consumption increased from 739.2 Watts to 853.2 Watts, an increase of 114 Watts. A validated CFD (Computational Fluid Dynamics) model was developed and predicted a loss in the enthalpy change from 11.7kJ/kg.d.a to 3.6kJ/kg.d.a. due to ambient temperature increasing from 22 °C to 40 °C and a loss of enthalpy change from 12.857kJ/kg.d.a to 5.524kJ/kg.d.a. due to increasing the ambient air humidity from 32% to 88%. This work high-lighted the impacts of ambient conditions on the performance of vapour compression cooling system in terms of increased power consumption and loss of cooling capacity.

Vapor compression air conditioning system with solar heat collector

THE RELEVANCE of the study lies in the fact that air conditioning systems in Iraq consume more than half of the electricity generation. During the summer, when temperatures rise, the demand for air conditioning increases, resulting in constant power outages. Consumers are starting to use local generation - diesel generators, which increase environmental pollution. THE PURPOSE. Consider the problems thermal energy from the sun is an ideal solution for reducing electricity consumption, increasing the performance of air conditioners, ensuring continuity of power supply and reducing pollution from diesel generators and power plants, as well as saving energy and reducing the consumption of fossil fuels. METHODS. When solving the problem, a comparison of options for standard and (hybrid using solar thermal energy) air conditioning systems was used. In a hybrid system, thermal energy enters the system from a solar collector built behind the compressor. Thermal parameters and level of electricity consumption were calculated. RESULTS. The article showed that a hybrid air conditioning system using solar thermal energy is more efficient than a traditional system, as it increases the cooling coefficient by (38.9 - 46.3%) and reduces electricity consumption by (56.89 - 66.66). %). CONCLUSION. The use of a hybrid air conditioning system in the climate of Baghdad city with a vapor compression air conditioning system reduced the electrical energy consumption of the compressor and increased the performance of the system, which will lead to increased reliability of power supply and eliminate the need to use local diesel generators.

Energy consumption and feasibility study of a hybrid desiccant dehumidification air conditioning system in Beirut

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 °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 5 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.

Infiltration of Outdoor PM2.5 Pollution into Homes with Evaporative Coolers in Utah County

Global use of energy-inefficient mechanical vapor-compression air conditioning (AC) is increasing dramatically for home cooling. Direct evaporative coolers (EC) offer substantial energy savings, and may provide a sustainable alternative to AC for homes in hot, dry climates. One drawback of ECs is the potential for infiltration of outdoor air pollution into homes. Prior studies on this topic are limited by small sample sizes and a lack of comparison homes. In this study, we used aerosol photometers to sample indoor and outdoor fine particulate matter (PM2.5) from 16 homes with AC and 14 homes with EC in Utah County, Utah (USA) between July 2022 and August 2023. We observed a significantly larger infiltration factor (Fin) of outdoor PM2.5 in EC vs. AC homes (0.39 vs. 0.12, p = 0.026) during summer. Fin significantly increased during a wildfire smoke event that occurred during the study. During the wildfire event, EC homes offered little to no protection from outdoor PM2.5 (Fin = 0.96, 95% confidence interval (CI) 0.85, 1.07), while AC homes offered significant protection (Fin = 0.23, 95% CI 0.15, 0.32). We recommend additional research focused on cooling pad design for the dual benefits of cooling efficiency and particle filtration.

Experimental study on high temperature performance of heat pipe and vapor compression compound cooling unit for communication base station

In order to solve the outstanding problems such as high energy consumption of traditional air conditioners in communication base stations, disordered air distribution in cabinets, and frequent high-temperature alarm of base band unit (BBU) in summer, a compound cooling unit of heat pipe and vapor compression air conditioner for communication base stations was developed, using a temperature control system with heat pipe cooling as the main and vapor compression air conditioners as the supplement, and the airflow form of downward sending up and back, high wind speed and internal circulation. The unit was applied to a communication base station in Zhengzhou to conduct the filed test. The results showed that BBU in the cabinet met the temperature control requirements of relevant standards under short-term high temperature and extreme high temperature conditions. There was no high temperature alarm. The average power of the compound cooling unit in the outdoor daily average temperature range of 24–28 ℃, 28–32 ℃, 32–36 ℃ and 36–40 ℃ is 127.7 W, 147.1 W, 314.2 W and 544.7 W respectively, and the energy saving rate is 71.9 %, 67.7 %, 39.5 % and 6.9 %, respectively. The air distribution in the cabinet can be further optimized to improve the temperature control effect of communication equipment and reduce the energy consumption of cooling system. This study has certain reference value for temperature control of communication equipment and energy saving of base station cooling system.

Simulation of vapour compression air conditioning system using Al2O3 based nanofluid refrigerant

The energy crisis, Greenhouse Gas (GHG) emissions, and Chlorofluorocarbon (CFC) emis-sions are major environmental issues at present. It is critical to achieve and reduce emissions and energy consumption through the use of environmentally friendly refrigerants. Utilizing an environmentally friendly refrigerant such as HFC-32 may offer a viable solution to the ozone depletion potential (ODP) and global warming issues. This study examines the effects of aluminium oxide (Al2O3) nanoparticles at volume concentrations of 0.06, 0.08, 0.1, 0.12, and 0.14% in pure refrigerants such as HFC-32 and R-410a used in air-conditioning systems based on the vapour compression refrigeration cycle. The thermophysical properties of pure and nanorefrigerants have been determined using REFPROP (NIST properties of fluid Refer-ence) and a theoretical formulation model using MATLAB software. The important outcomes of HFC-32 nanorefrigerant show the maximum performance with 0.14% alumina nano addi-tives which results in a 46.14% increase in the coefficient of performance (COP) and massive power savings upto 31.59%. Thermal conductivity exhibited an increase with an increment in nanoparticle concentration. Maximum thermal conductivity of 0.172 W/m-K is recorded in the case of HFC-32/Al2O3 nanorefrigerant with 0.14% volume concentration. The net re-frigeration effect of pure refrigerants (R410a and HFC-32) is 77% and 79% and on addition of nanorefrigerants to the pure the net refrigeration effect increases to 81.2% and 83.5% for R410a and HFC-32 respectively.

Study of Solar Photovoltaic Array for Air Conditioning System

The vapor compression refrigeration (VCR) and air conditioning systems are widely used for cooling, refrigeration, air conditioning, heating purposes and consumes more than 33% of the world energy. Solar energy is available abundantly as renewable energy source in summer when requirement of comfort is in peak demand. The electrical energy is replaced with solar energy by properly selecting solar panels, battery, inverter, charge controllers for storing fruits and vegetables in rural areas due to uncertain pattern of grid electricity. In the paper, solar power VCR system is designed and simulated with Simulink to estimate the performance in terms of irradiance and temperature. It is found that with rise in irradiance, current and power outcome increases. The solar system is CO2 free with substantial saving of 9700 whereas conventional VCR system produces 5292 kg of CO2 during life time of solar PV system.

An insight into environmental footprints of emerging air-conditioning systems towards sustainable cities

In this study, the environmental impacts of six conventional and modern air conditioning systems, including vapor-compression air conditioning (VAC), hybrid membrane-based air conditioning (HMBAC), desiccant enhanced evaporative air conditioning (DEVap), solar HMBAC, solar DEVap, and inverter VAC, are analyzed using a cradle-to-gate life cycle assessment (LCA) approach. The assessment is based on climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, human toxicity, photochemical oxidant formation, ecotoxicity, water depletion, and fossil fuel depletion impacts. The LCA findings reveal that membrane-based systems (HMBAC and DEVap) are highly environmentally-friendly in comparison to the regular VAC systems (household split coolers), showing the capability of membranes in developing efficient air conditioning systems. In addition, solar-assisted systems reduce seven out of eleven environmental impacts, while they cause severe eutrophication, marine and freshwater ecotoxicity, and human toxicity consequences. Furthermore, it is unveiled that the inverter can reduce up to 38% of the environmental impacts of VAC systems which are the most common air conditioning system in buildings. Therefore, the manipulation of the inverter system in VACs can be considered as one of the short-term solutions in reducing the environmental footprints of air conditioning. Finally, the sensitivity analysis is applied to show the reliability of the outcomes.

Experimental verification of artificial neural network scalability for performance monitoring of multi-split type air conditioners

The scalability of a cost-effective and non-intrusive method for performance monitoring of multi-split type air conditioners is experimentally demonstrated on systems with different nominal capacities and design features. The method relies on an artificial neural network (ANN) technique, which uses easily measurable parameters representative of the refrigerant cycle and manipulated control parameters as the input for predicting the real-time cooling capacity of the system. Two air conditioning units intended for training and testing of the ANN model, are tested while being operated with their native control system in a broad range of experimental conditions for verifying the proposed methodology. The model scalability relies on the similarity of the fundamental working principles of vapor compression air conditioners. It is confirmed that temperature measurements in selected locations of the refrigerant pipeline and the total power consumption represents a suitable set of inputs for ensuring high prediction accuracy and ANN model scalability with rated system specifications from the product catalogue. The results show that the proposed monitoring method achieves accurate and generalizable predictions of the cooling capacity while limiting the relative error to below 10%.

Real life test of a novel super performance dew point cooling system in operational live data centre

This paper presents the development and application of a super performance dew point cooling technology for data centres. The novel super performance dew point cooler showed considerably improved energy saving and carbon reduction for data centre cooling. The innovations of this technology are built upon a series of technological breakthroughs including, a novel hybrid flat/corrugated heat and mass exchanging sheets, an innovative highly water absorptive and diffusive wet-material for the sheets which enable an intermittent water supply with well-tuned water pressure and flow rate, and the optimised fan configurations. Following a list of fundamental research including theoretical, numerical and lab experimental testing of a small scale prototype system, a specialist 100 kW rated data centre dew point cooling system was dedicated designed, constructed, installed and real life tested in an operational live data centre environment, i.e., Maritime Data Centre at Hull (UK) to investigate its dynamic performance, suitability and stability for application in operational data centre environment conditions.During the testing period, the system showed its reliability and capability to remove a tremendous amount of heat dissipated from the IT equipment and maintain an adequate space temperature in the operational live data centre. The dynamic data collection and analysis during the continuous testing and monitoring period showed the average COP of 29.7 with the maximum COP of 48.3. Compared to the existing traditional vapor compression air conditioning system in the data centre, the energy saving using the super performance dew point cooling system is around 90 %. The work presented in this paper include detailed innovation aspects of the technology and the system operation, as well as the established bridging knowledges, methodology and technical procedure for bringing this new technology into real life operation which involve in data centre survey, optimum design and modularization of the specialist cooling system for data centre application, proven system installation, operating method and cooling air management for data centre as well as the assurance of the continuous sufficient cooling supply to the data centre.

Assessing Energy Performance and Environmental Impact of Low GWP Vapor Compression Chilled Water Systems

The global concern regarding the environmental repercussions of refrigerants has escalated due to their adverse effects. These substances deplete the ozone layer and intensify the greenhouse effect. International agreements such as the Montreal and Kyoto Protocols and COP21 have imposed restrictions on refrigerants with high global warming potential (GWP) to address these issues. This study aims to explore the feasibility, energy efficiency, and environmental impact of utilizing the HFO (hydrofluoric-olefin) refrigerant R1234ze as a substitute for HFCs (hydrofluoric-carbon) (R134a, R407C, and R410A) and HCFCs (R22) in air-cooled vapor compression refrigeration and air conditioning systems. To determine their effectiveness, we evaluate the energy performance of various refrigerant operating cycles across a wide range of ambient and evaporating temperatures. Additionally, we conduct environmental impact analyses based on the total equivalent warming impact (TEWI) parameter calculated for commercially available chillers that utilize the fluids mentioned above. Our findings indicate that vapor compression chilled water systems employing R1234ze exhibit the highest performance coefficient and the lowest annual TEWI.

Analysis on desiccant coated heat exchangers based on a new performance parameter and thermodynamic model

Performance of traditional vapor compression air-conditioners can be improved by achieving sensible and latent loads decoupling via the use of desiccant coated heat exchangers (DCHEs). Performance evaluation of the DCHE is mainly based on its dehumidification capacity. However, extra loss of cooling power, caused by the switch of dehumidification and regeneration phases, has not been investigated in previous articles yet. Hence, assessment for cooling power utilization efficiency (CPUE) of the DCHE is essential. In this paper, a thermodynamic model based on the first law of thermodynamics is developed and the CPUE is proposed. Further, a fundamental parametric investigation is conducted to understand the effect of different desiccant types, structure parameters and operating conditions of air and water flow. The results show that ratio of metal to desiccant and outlet air temperature in dehumidification process are the key factors on the CPUE. CPUE of metal–organic framework DCHE is more than 0.95, which is superior to the other investigated desiccant types. Then, thermodynamics model of a vapor compression air conditioner is built to evaluate the electrical coefficient of performance of the system using DCHEs. The results for different desiccant types can achieve 6.5–8.2 at 15/40 °C evaporation/condensation temperatures.

Sustainable Cooling in a Warming World: Technologies, Cultures, and Circularity

Cooling is fundamental to quality of life in a warming world, but its growth trajectory is leading to a substantial increase in energy use and greenhouse gas emissions. The world is currently locked into vapor-compression air conditioning as the aspirational means of staying cool, yet billions of people cannot access or afford this technology. Non–vapor compression technologies exist but have low Technological Readiness Levels. Important alternatives are passive cooling measures that reduce mechanical cooling requirements and often have long histories of local use. Equally, behavioral and cultural approaches to cooling play a vital role. Although policies for a circular economy for cooling, such as production and waste, recovery of refrigerants, and disposal of appliances, are in development, more efforts are needed across the cooling life cycle. This article discusses the knowledge base for sustainable cooling in the built environment and its significant, interconnected, and coordinated technical, social, economic, and policy approaches.

Performance assessment of integrated liquid desiccant dehumidification with vapor-compression system for energy-efficient air conditioning applications

The present study aims to integrate desiccant dehumidification systems and vapor-compression air conditioning (VC) systems for energy-efficient air conditioning applications. A numerical model is developed for a dehumidifier/regenerator module based on the governing mass, energy, and species balance equations. Subsequently, the desiccant system is integrated with the VC system to investigate the overall system performance. The novelty of the present work is in its exploration of the integration of desiccant systems. The share of dehumidifier load in overall system is studied, and performance of the integrated system is compared with that of a standalone VC system. Trade-off analysis is also performed in consideration of all performance parameters. The comparative results reveal that a significant amount of the total latent heat load is controlled by the dehumidifier. Specifically, it is observed that the integrated system can improve the COP by 40.8–74.8% relative to the standalone VC system under different operating conditions.

Experimental performance of a three-fluid desiccant contactor using a novel ionic liquid

• Novel Ionic Liquid that is not corrosive to aluminum is used as liquid desiccant. • New three-fluid fin-tube desiccant contactor fabricated using aluminum. • Experimental performance of the fin-tube contactor using IL solution is investigated. • The fin–tube contactor showed superior performance than the packed bed contactor. • Lower solution flow rates and pumping power is expected using the fin–tube contactor. The experimental performance of a new three-fluid fin–tube contactor using a novel ionic liquid desiccant solution is investigated and compared with those of an adiabatic packed bed contactor with LiCl solution for liquid desiccant air conditioning system applications. Owing to the compatibility of the ionic liquid solution with aluminum, a fin–tube contactor is manufactured to exploit internal cooling from a third fluid. The results indicate the superior dehumidification performance of the fin–tube contactor, which yielded an outlet air humidity ratio of 10.5 g w ·kg da -1 at a solution mass flux of 3.06 kg·m −2 ·s −1 , as compared to a similar humidity ratio at a solution mass flux of 4.98 kg·m −2 ·s −1 achieved by the packed bed contactor. In terms of cooling performance, the outlet air temperature of the fin–tube contactor is 21.9 °C, which is lower than that of the packed bed contactor even at its highest solution mass flux. This indicates that the cooling performance of the fin–tube contactor has minimal dependence on the solution mass flux in achieving cooling effect, owing to the cooling medium flowing inside the tubes. Relatively lower solution pumping power than that of the packed bed contactor can be expected from the fin–tube contactor, in addition to the ability to achieve comfortable and hygienic indoor air at a cooling medium temperature of 17 °C or higher, the ionic liquid desiccant and three-fluid fin–tube contactor pair for liquid desiccant air conditioning system is elevated a step higher as an alternative to vapor compression air conditioning system.