Review of liquid desiccant technology for hvac applications andrew lowenstein, phd member ashrae received april 16,2008. Desiccant dehumidification brochure stulz desicair solutions and services brochure revb file. This system has a great potential to provide thermal comfort in places where air humidity is. Dws are constituted by identical channels aligned lengthwise and distributed into concentric layers. Hybrid desiccant cooling system is used desiccant wheel for dehumidification and then further cool in indirect evaporative cooler, the solar energy is used for desiccant regeneration. To find effect of dehumidification capacity on the performance of cooling system, four configurations of desiccant cooling system have been investigated. This document provides an overview of desiccant cooling technology and provides readers with reference. Opencycle solid desiccant systems fixed bed systems not used chemical industry rotary systems.
Gro w ing use o f ac s is ex pected be caus e of g loba l warm ing. Eerc desiccant dry cooling the eercs ddc concept uses a hygroscopic desiccant working fluid to dissipate thermal energy directly to the ambient air. Figure 5 shows another liquid desiccant cooling system in which strong and weak desiccant flows in the whole system. The thermally driven cooling cycle is a combination of evaporative cooling with air dehumidification by a desiccant, i. Worek stony brook university may 12, 2014 arpae meeting chicago, il. They can be used as standalone systems or with conventional airconditioning to improve the indoor air quality of all types of conditioned spaces. Desiccant cooling systems have been considered as an efficient method of controlling moisture content in supply air.
Simulation and energy efficiency analysis of desiccant. The addiction of a desiccant dehumidifier to an evaporative cooling air conditioning system provides a humidity control separate of the temperature control. In recirculation mode, also called recirculation cycle, the process inlet air is the return air from the. This property of desiccants is due to its low vapor pressure. Optimization of the open absorption desiccant cooling system has been carried out in the present work. A desiccant system that uses strong desiccant at 43% by weight and weakens the desiccant to 35% will be able to achieve storage density of 5 gallons gal of desiccant per latent tonhourhr of cooling provided. Use the following link to access a scalable pdf file. In these systems, a desiccant removes moisture from the air. This document provides an overview of desiccant cooling. Solar cooling, dehumidification and air conditioning technion israel institute of technology 23 schematic description of desiccant system airair h. The desiccant cooling system consist of three main. Our purge technology reduces regeneration energy by up to 30% and by means of cooler supply air the need of post cooling.
Now days, air conditioning systems are a must for almost every commercial and residential building to achieve comfortable indoor conditions. Desiccant dehumidification systems have the capability to dry the air to any desired humidity level, which is an advantage for certain applications. Advantages of desiccant enhanced cooling it extends the climatic applicability scope of the evaporative cooling. Review of liquid desiccant technology for hvac applications. Since mass transfer occurs between the system and its envi ronment, they are commonly referred to as opencycle systems. To some extent, desiccant performance can be precisely described, but most commonly, the final choice of which desiccant best suits a given situation, how much of it to use, and in what form, is made based on testing and practical experience. Desiccant based systems are more economical than refrigeration systems at lower temperatures and lower moisture levels. The scheme thus formed is a desiccant cooling system. An evaporative and desiccant cooling system for an. Because of the low thermal cop and hightemperature regeneration requirement in previous desiccant. Advantages of desiccant enhanced cooling it extends the climatic applicability scope of the evaporative cooling to the hot and humid zones.
Executive summary of the advanced desiccant cooling and. Our purge technology reduces regeneration energy by up to 30% and by means of cooler supply air the need of post cooling can be reduced by up to 70%. Hybrid desiccant cooling system free download as powerpoint presentation. Desiccant cooling system a novel technique for air. Ddc is intended to address the key shortcomings of conventional dry cooling. In desiccant cooling cycles, the desiccant reduces the humidity of the air by removing moisture from the air. Inside the processor, the desired cooling source for airs dehumidification is indoor exhaust airs evaporative cooling. How the desiccant wheel works the munters desiccant wheel works on the principle of sorption, which is the adsorption or the absorption process by which a desiccant removes water vapor directly from the air. This structure is obtained by means of a support material onto which the desiccant. Desiccant evaporative cooling basically absorb the latent heat in the air i. Gaia research have been undertaking research to determine whether desiccant cooling technology using gassolar generated low temperature heat for regeneration, might be reliable and cost effective in the uk in the near future. If tight temperature control is also required, a small sensible only post cooling coil is employed. Liquid dessicant solar airconditioner system overview. The addiction of a desiccant dehumidifier to an evaporative cooling air conditioning.
Successful operation of the desiccant heat pump in the cccusc energy laboratory research house has demonstrated that a heating cycle utilizing the heat of sorption of a concentrated desiccant could be added to a desiccant cooling system, thus creating an opencycle liquid desiccant. Desiccant cooling systems process water vapor in the earths atmosphere. The absorbent solution, kathene, is a desiccant solution composed of lithium chloride salt and water. Adsorption and absorption systems overview by william m. Kathene is nontoxic, will not vaporize, and is not degraded by common airborne contaminants. A finite difference method is used to simulate the combined heat and mass transfer processes that occur in the liquid desiccant regenerator which uses calcium chloride cacl2 solution as the working desiccant. For this purpose, liquid or solid materials can be employed. The munters desiccant wheel stands out as the most energy efficient technique for creating humidity controlled environments. Psychrometrics is the field of engineering concerned with the amount of moisture as vapor in the atmosphere. These systems all use a liquid or solid material called a desiccant.
May 29, 2012 this breakthrough combines desiccant materials, which remove moisture from the air using heat, and advanced evaporative technologies to develop a cooling unit that uses 90 percent less electricity and up to 80 percent less total energy than traditional air conditioning. The increasing energy demand, and increasing oil prices and. Through performance studies of desiccant cooling system, it has proven its feasibility and advantages of energy and cost saving in different climatic conditions. They do not use any ozonedepleting coolants and consume less energy as. Replacementdesiccantinstructions is provided by general air products. In this system, desiccant wheel is an important component in which. A soliddesiccant cooling system for greenhouses amel rjibi, sami kooli, amen allah guizani research and technology center of energy, thermal processes laboratory, hammam lif, b. Desiccant cooling systems are energy efficient, cost effective, and environmentally safe. Saturated, compressed air passes through vessel one where the desiccant. The rotating heart of munters dehumidifiers how the desiccant wheel works the munters desiccant wheel works on the principle of sorption, which is the adsorption or the absorption process by which a desiccant.
However, if activated alumina is used in a regenerative dryer and the desiccant. Harriman iii member ashrae dean plager and douglas kosar member ashrae inetyfive years since willis carrier began the modern era. Desiccant cooling system, evaporative cooling, solar regeneration, compounding of desiccant wheel, modeling of desiccant wheel. The resulting dry air is somewhat cooled in a sensible. Desiccant rotary wheels do not reduce the air energetic load. Kathabar liquid desiccant dehumidification systems operate on the principle of chemical absorption of water vapor from air. Desiccant cooling is an environment friendly air conditioning system used as a option to conventional vapor compression system. Moreover, the solar desiccant cooling system, depending on the cooling loads and environmental conditions, will use one of the above mentioned cooling modes, i. Figure 1 shows the experimental setup of system that conducted to the test room by ducts. Design and testing of a liquid desiccant dehumidifier. There are common features to the systems, along with features unique to. Kini this paper describes recent published design advances that have been made in desiccant. Since the second coil is used for sensible cooling only, it will operate dry.
How desiccant drying works sullair desiccant dryers have a dual tower design in which both vessels are filled with desiccant material. Instructionsparts dryaire desiccant system 310595f model 6760 maximum operating pressure. The test room has a length 3 m, width of 2 m, and height of 3 m. Analysis of a solid desiccant cooling system with indirect evaporative cooling. Solar assisted desiccant air conditioning system for hot and. Desiccant cooling technology resource guide 2 executive summary purpose of this resource guide this resource guide is an easy to use reference source for investigating, evaluating and installing desiccant cooling technologies. Since the second coil is used for sensible cooling only, it will operate dry this can be advantageous in that it reduces the opportunity for biological contamination. An evaporative and desiccant cooling system for air conditioning in humid climates evaporative cooling operates using water and air as working fluids. The air to be dried passes through the desiccant wheel and the desiccant removes the water vapor directly from the air and holds it. Solar desiccant cooling systems focus on the dehumidification of air as a means of cooling air for a building space. Pressure drop is slightly lower than 18 25mm material. Modelling and analysis of a desiccant cooling system using.
The impact of relative humidity, heat of adsorption and carryover heat 1 perhaps the simplest and best way to describe the thermodynamic performance of the semco passive dehumidification wheel is to compare it to a traditional active desiccant. Solarpowered, liquiddesiccant air conditioner for low. If size is not known or specified, the 18 25mm size is usually satisfactory. All the components of an lds such as dehumidifier, regenerator, packing material and liquid desiccant properties along with its energy storage. For more detailed information, please refer to the following references. Solar assisted desiccant cooling system is an attractive and cost effective application for air conditioning system. The desiccant cooling can be either a perfective supplement to the traditional vapour compression air conditioning technology to attenuate the effects of its drawbacks, or an alternative to it for assuring more accessible, economical, and cleaner air conditioning. To find effect of dehumidification capacity on the performance of cooling system, four configurations of desiccant cooling.
A liquid desiccant dehumidifier would typically be used in series with a sensible cooling device to reduce the airs drybulb temperature. Pdf desiccant cooling systems have been considered as an efficient method of controlling moisture content in supply air. However, there are some technical challenges of developing an efficient heat pump that runs. Therefore, production of energy for heating, cooling, air conditioning systems also leads to increasing of the amount of carbon dioxide in the atmosphere. Desiccant cooling systems can be operated in a recirculation mode, in ventilation mode, dunkle cycle and wetsurface heat exchanger cycle. Analysis of a solid desiccant cooling system with indirect evaporative cooling bellemo, lorenzo publication date. The impact of relative humidity, heat of adsorption and. Dehumidification and cooling loads from ventilation air by lewis g.
In this system, desiccant wheel is an important component in which dehumidification takes place by means of adsorption process. Simulation and energy efficiency analysis of desiccant wheel. Desiccant based airconditioning equipment is ideally suited to efficient dehumidification of building ventilation air, and when used in combination with conventional, vapor compression, air conditioning. The dry air is cooled using either evaporative cooling or the cooling. Desiccant, air conditioning, dehumidification, evaporative cooling, thermal energy. Optimization of desiccant absorption system using a genetic.
Desiccant cooling system a novel technique for air conditioning. Gaia research have been undertaking research to determine whether desiccant cooling technology using gassolar generated low temperature heat for. Desiccant cooling offers advan tages as an option for building air conditioning, including use of lowtemperature solar heat as the driving energy source, a broad. Apr 07, 2020 download liquid desiccant cooling system newest. Design and testing of a liquid desiccant dehumidifier p. Its operation is based on the use of a rotary dehumidifier desiccant wheel dw in which air is dehumidified. Pdf liquid desiccant cooling system newest free download pdf. Desiccant cooling technology resource guide cedengineering.
These systems all use a liquid or solid material called a desiccant to remove water vapor from the air. Replacementdesiccantinstructions general air products. Modelling and analysis of a desiccant cooling system. As the desiccant system can operate on low heat, heat energy can be provided through solar thermal systems or any waste heat source from chimneys, power plants, etc. Member member asae asae abstract adehumidification system employing liquid desiccant was designed, constructed, and tested to determine the effect desiccant and air temperatures have on water vapor absorption rate. Hvac systems that integrate several desiccant wheels in the air handling unit have been discussed by kodama et al. This process, if optimized, can have a lower cooling load compared to the base case. The thermally driven cooling cycle is a combination of evaporative cooling with air dehumidification by a desiccant. The desiccant dewpoint cooling ddc system 10 is a specific dec system, constituted by a desiccant wheel dw made of silica gel, a heat recovery unit hru, a dew point cooler dpc, and a heat.
Typically, a desiccant dehumidification system is utilized for applications below 45% rh down to 1% rh. Hybrid desiccant cooling system is used desiccant wheel for dehumidification and then further cool in indirect evaporative cooler, the solar energy is used for desiccant. Description download liquid desiccant cooling system newest comments. Analysis of a solid desiccant cooling system with indirect. Liquid desiccant systems overview alfa laval kathabar offers a full line of liquid desiccant system series including, fv, fh, fp and sp. Solar assisted desiccant air conditioning system for hot. The desiccant cooling can be either a perfective supplement to the traditional vapour compression air conditioning technology to attenuate the effects of its drawbacks, or an alternative to it for assuring. Report liquid desiccant cooling system newest please fill this form, we will try to respond as soon as possible. Analysis of advanced solar hybrid desiccant cooling. The fact that peak cooling demand in summer is associated with high solar radiation offers an excellent opportunity to exploit solar thermal cooling technologies. The performance of any desiccant varies with temperature and both relative humidity and absolute humidity. Liquid desiccants for dehumidification in building. An overview of opencycle desiccant cooling systems and.
Analysis of desiccant cooling system gaurav pundir1 and s n mishra1 corresponding author. Figure 1 shows a dehumidifier wheel type honeycomb. Liquid desiccant system an overview sciencedirect topics. Hybrid desiccant cooling system air conditioning hvac. Desiccant cooling systems require electricity to operate pumps and fans and heat energy to preheat the desiccant solution for regeneration. Dehumidification and cooling loads from ventilation air. An evaporative and desiccant cooling system for air. The solar hybrid desiccant cooling system was established near the test room located in solar technology park, ukm malaysia. The primary objective of this project was to demonstrate the capabilities of a new highperformance, liquid desiccant dedicated outdoor air system doas to enhance cooling efficiency and comfort in.
A study of desiccantbased cooling and dehumidifying system in. They are used as standalone systems or with conventional airconditioning. A liquid desiccant fresh air processor is presented whose driven force is lowgrade heat 6570. Of the solar cooling options availabie open cycle solid desiccant cooling looks very promising. Solar thermal cooling can help alleviate the problem. Desiccant cooling systems are basically open cycle systems, using water as refrigerant in direct contact with air. Thus, in many applications, a dx or chilled water pre cooling coil is mounted directly at the dehumidifier inlet. They do not use any ozonedepleting coolants and consume less energy as compared with the vapour compression systems. It consists in water evaporation, through the passage of an air flow, thus decreasing the air temperature. An overview of opencycle desiccant cooling systems and materials.