T.s. Ge

• Doctor of Engineering
• Professor at Institute of Refrigeration and Cryogenics

Humidity always accompanies human beings’ life and industry production. A high humidity environment not only induces health hazards easily but also aggravates energy consumption. Desiccant-based internally-cooled dehumidification using porous sorbents represented by desiccant coated heat exchanger (DCHE) is regarded as the high efficient humidity r...

The theoretical analysis of the field synergy is tried to apply to desiccant coated heat exchangers (DCHEs) to clarify its coupled heat and moisture transfer characteristics and the way to enhance the characteristics. In this paper, the heat and moisture transfer model of DFHE is established and verified by comparison with experimental data. Three...

Desiccant coated heat exchanger (DCHE), which can be adopted to construct a solar cooling system or desiccant heat pump system, can realize both sensible and latent load removal to provide comfortable supply air. Although it is difficult to avoid condensation in a practical application, the condensation condition of DCHEs is rarely studied. In this...

Nowadays, waste-to-energy systems have attracted more and more attentions. Gasification technology is one of the most important methods of waste-to-energy utilization. For further using the residual heat of the gasification system, a desiccant dehumidification unit with heat recovery using desiccant coated heat exchanger (DCHE) driven by waste heat...

A microchannel heat exchanger coated with silica gel is investigated in this paper, and a series of condensation experiments are implemented under the simulated high temperature and high humidity conditions to analyze the dynamic performance of the microchannel desiccant coated heat exchanger (DCMHE). The sign of judging the presence of condensatio...

In this study, performance of silica gel rotary wheel system (SRWS) to increase humidity of indoor air in winter is investigated in China. First, an experimental setup is built up to obtain humidification performance of the system under Shanghai winter conditions, and effects of main operation parameters are analyzed. Results show that SRWS can pro...

Solid desiccant, featuring thermally-driven mass transfer, is nowadays a hotspot in the field of mass adsorption/separation, energy allocation and water harvesting. Former studies indicate that the efficiency in such systems is dominated by the adsorption dynamics of the desiccant-based components. Accordingly, enormous efforts have been attempted...

Desiccant coated heat exchangers (DCHEs), utilizing an inner cooling source to remove sorption heat, are promising alternatives for evaporators and condensers (DCEs/DCCs) in vapor compression (VC) heat pumps. A mathematical model is necessary to facilitate the design, analysis and performance prediction of the component and the relevant systems. In...

Removing benzene from indoor space plays an important role in indoor air purification. A novel filter with vegetal fiber paper (VFP) as matrix hosting silica gel is proposed in this paper for benzene removal. In order to investigate the feasibility and performance of this idea, firstly, three pieces of VFP samples impregnated with different amounts...

A kind of wood pulp fiber paper (WPFP) was proposed as candidate for the matrix of desiccant wheel. Silica gel was coated on WPFP by impregnation method and the corresponding coating ratio was obtained and analyzed. Then the thermal conductivity, pore structure and adsorption/desorption performances of WPFP coated with silica gel were tested and an...

The desiccant coated heat exchanger (DCHE), utilizing inner cooling source to ease the side effect of sorption heat, is now a hot spot in the field of humidity control. Meanwhile, when incorporated in heat pumps, the function of DCHEs is expected to be further extended. Named as solid desiccant heat pump (SDHP), such system can realize weakly-coupl...

Two types of DCHEs, desiccant coated microchannel heat exchanger (DMHE) and desiccant coated fin-and-tube heat exchanger (DFHE), are manufactured and tested. The heat transfer, mass transfer and pressure drop performances of two DCHEs are analyzed and compared by experimental results. In the same conditions, the heat transfer coefficients of DMHE a...

Experimental investigation on the performance of novel composite desiccant Silica Gel and Sodium Acetate Coated Heat Exchanger (SASCHE) is conducted for typical summer and winter seasons in the city of Shanghai, China. First, effects of main parameters such as regeneration temperature, hot and cooling water temperature, inlet air velocity, thermal...

Indoor air quality including temperature, humidity and cleanliness has attracted more and more attention recently. Rotary desiccant wheel system provides a good solution to improve indoor air quality due to it can realize both TVOC and moisture control. In order to analyze practical performance of desiccant wheel, in this paper an experimental setu...

In cold climates, keeping proper temperature and humidity level is essential to ensure a comfortable and healthy building environment. In this paper, a new method is developed to meet the demand for humidifying the indoor air in winter by using desiccant coated heat exchanger (DCHE) as a heating and humidifying unit during the regeneration process....

Recently a novel concept of water-sorbing heat exchanger has been proposed, which can independently handle latent and sensible loads at the same time and provide a very promising high-efficient solution for temperature and humidity control. Obviously, moisture uptake behavior has great influence on heat exchanger's performance. Here, a series of ex...

Hybrid solid desiccant and vapor compression system is developed to realize independent control of temperature and humidity. However the large volume has always hindered further development and heat pump system based on desiccant coated heat exchanger (DCHE) is proposed to solve the problem. It's DCHE instead of conventional sensible heat exchanger...

Comfortable, efficient and affordable heating, ventilation and air conditioning (HVAC) systems in buildings are highly desirable to achieve zero energy building effort. Traditional vapor compression air-conditioners hold a lower COP (coefficient-of-performance) (typically 3.2–3.8) because it often operates at a lower evaporation temperature (5–7 °C...

Desiccant-coated, water-sorbing heat exchanger has been proposed and investigated which shows a great advantage to independently treat the sensible and latent heat load but without sacrificing compactness and comfort. Here, a theoretical and experimental study was made to investigate and predict its dynamic behaviors of heat and mass transfer in re...

Desiccant wheel dehumidification air conditioning system makes full use of the principle of desiccant dehumidification and evaporative cooling. Besides desiccant material, the substrate also plays an important role in improving the dehumidification performance of a rotary desiccant wheel. The objective of this paper is to present the state of the a...

In this paper, composite silica gel and potassium formate as typical organic weak acid salts is proposed to use in desiccant coated heat exchanger (DCHE). An experimental study on dynamic adsorption performance of desiccant coated metal sheet samples is conducted to obtain results with different proportions of silica gel and potassium format. A DCH...

In this study, a general-purpose test platform is built to test and compare the heat and mass transfer characteristics. Two heat exchangers of different length of fins conventional/desiccant coated (LDCHE and SDCHE) are experimentally investigated and compared with the heat and mass transfer characteristics. Experimental results show that compared...

The solid desiccant heat pump (SDHP) system is a novel thermodynamic appliance, intended to improve the energy efficiency of the conventional air conditioning. In the SDHP, desiccant coated heat exchangers are adopted as the evaporator and the condenser instead of the conventional sensible heat exchangers. This article aims to investigate the perfo...

As a novel solid desiccant component, solid desiccant coated heat exchanger (DCHE) is proposed by coating solid desiccant material to conventional sensible heat exchanger (SHE) surface. The idea of adopting a DCHE and an SHE operating in series is proposed and an experimental setup was built up to investigate its performance. Results show that with...

Condensation occurring on metal cabinet surface seriously affects the maintenance and operation safety. In order to prevent condensation, desiccant coating surface method is proposed and investigated in this paper. Basic operation model of desiccant coated cabinet to realize anti-condensation and regeneration is first introduced, then an experiment...

Using conventional fossil fuels causes both energy crisis and environmental pollution. Renewable energy with the merits of almost unlimited availability and environmental-friendliness provides a perfect solution to the problem. Solar energy is widely recognized as one of the most important renewable energy resources due to its even distribution, sa...

In this paper, a desiccant coated heat exchanger system is installed and tested under typical winter condition at Shanghai. Effects of hot water temperature, hot water mass flow rate and regeneration air flow flux are discussed as vital factors impacting system performance. It is found that the optimum regeneration hot water temperature and mass fl...

In this study, the heat and mass transfer characteristics of desiccant coated heat exchanger (DCHE) and conventional heat exchanger are compared by experiments. A general-purpose test platform is built to test and compare the characteristics above. Based on the designed experimental setup, two heat exchangers of different depths of fins conventiona...

In this paper, a desiccant coated heat exchanger (DCHE) system driven by solar energy is built and tested under winter condition. The purpose of this experimental research is to explore the heating and humidification performance of DCHE system. Effects of hot water temperature, hot water mass flow rate and regeneration air flow flux are discussed a...

Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8–3.8) owing to the cooling-based dehumidific...

In terms of solar thermal-driven air-conditioning cycles, in addition to the common solar-driven solid adsorption cycles, liquid absorption cycles, and desiccant cooling cycles, there are also some other types of solar-powered cooling systems in which solar-driven ejector cooling cycles and Rankine cycles are recently drawing more and more attentio...

The solar heating and cooling systems are among the best solutions for the current energy and environment issues. In this chapter, the background and overview of the solar heating and cooling systems are given. In these systems, the energy sources are the solar power, and the consuming components include the heating and cooling devices. In order to...

Conventional air source heat pump system faces several challenges when adopted in winter season. Solid desiccant air conditioning system can provide humidification and heating power simultaneously and can be driven by low grade thermal energy; it provides a good alternative for air source heat pump systems. However, conventional solid desiccant air...

Traditionally, heat and mass transfer on adsorptive heat exchanger (AHE) is believed to be coupled, the concept of which makes it is hard to design and control the AHE optimally. Here, a novel concept of weak coupled heat and mass transfer is proposed to explain the dynamic behaviors of heat exchanging and moisture removal on AHE, which is based on...

A hybrid solar hot water and Bi2Te3-based thermoelectric generator (TEG) unit using a heat pipe evacuated tube collector with mini-compound parabolic concentrator (mini-CPC) is proposed. In this unit, the heat from the heat pipe evacuated tube solar collector is transferred to the hot side of TEG. Simultaneously, water cooling is used at the cold s...

Advances in Solar Heating and Cooling presents new information on the growing concerns about climate change, the security of energy supplies, and the ongoing interest in replacing fossil fuels with renewable energy sources. The amount of energy used for heating and cooling is very significant, estimated, for example, as half of final energy consump...

A novel fresh air desiccant system using silica gel coated heat exchanger is fabricated and introduced with heat recovery in this paper. It can be proved that heat recovery device can provide significant benefits to the desiccant performance of the system. The output total cooling capacity increases because of a lower supply air temperature. In add...

A DCHE (desiccant coated heat exchanger) is a novel solid desiccant cooling component with desiccant coated onto the surface of a fin-tube heat exchanger. In the paper, carbon based composite desiccants were developed and studied for DCHE systems. Composite desiccants were fabricated by impregnating LiCl into pores of activated carbon and activated...

The objective of this paper is to validate the practical performance of a novel self-cooled solid desiccant cooling system which consists of DCHE (desiccant coated heat exchanger) and regenerative evaporative cooler. In the system, part of the outlet air from the desiccant coated heat exchanger is pumped into the evaporative cooler to produce cooli...

A new type of solid desiccant dehumidification cycle with internal heat recovery based sorptive material coated heat exchanger (SCHE) is proposed. This system can realize waste heat recovery from exhausted air in regeneration process, in which a heat recovery device (HRD) is adopted. The performance evaluation of the novel cycle is compared with th...

A DCHE (desiccant coated heat exchanger) is a novel solid desiccant component with desiccant coated onto the surface of a fin-tube heat exchanger, in which desiccant coated aluminum-fin is an important part. It has an impact on overall performance of the whole desiccant cooling system. In this study, different zeolite-like powders (SAPO-34 and FAPO...

In this paper, the heat and moisture transfer characteristics of a desiccant dehumidification unit using fin-tube heat exchanger with silica gel coating have been experimentally investigated. The present study focuses on the analysis of air side heat and moisture transfer performance in dehumidification mode. The empirical formula on Nusselt and Sh...

Desiccant coated heat exchanger (DCHE) is a newly developed fin tube heat exchanger with desiccant coating on the surface, it can handle sensible and latent load simultaneously. In this paper, composite desiccant based on silica gel and lithium chloride is adopted as solid adsorbent in DCHE. Equilibrium isotherms of aluminum foils coated with silic...

A Bi2Te3 TEC with silica aerogel encapsulation is developed. Silica aerogel with different thicknesses is filled in the void spaces around the TE legs and started from cold-side ceramic plate. A three dimensional mathematical model for the TEC is developed. This model considers the effect air gap and silica aerogel. (Bi0.2Sb0.8)2Te3 and Bi2(Te0.97S...

In this paper, water-cooled thermoelectric cooler (TEC) for central processing unit (CPU) is developed. Two temperature controls for TEC are proposed and compared to prevent condensation on CPU and save energy. Performances of TEC with the two temperature controls are experimentally investigated under different operating conditions and environmenta...

Solid composite desiccants are fabricated by impregnating LiCl into pores of SBA-15 and MCM-41 mesoporous silicates. In the study, characteristics including textural properties and equilibrium and dynamic water sorption were tested and analyzed. Research on nitrogen adsorption suggested that because of the impregnated salt, composite desiccants wer...

Desiccant coated aluminum-fin is an important part in desiccant coated heat exchanger (DCHE). It will affect the overall performance of this novel solid desiccant component. In the paper, different silica gel-LiCl composite desiccant coated aluminum sheets were fabricated and some key parameters were studied. Nitrogen adsorption suggested that text...

Desiccant coated heat exchanger provides a promising option for desiccant cooling system, since it can handle sensible load and latent load simultaneously within one component. It is fabricated by coating desiccant material on the surface of conventional fin-tube heat exchanger. In order to enhance the performance of conventional silica gel coated...

Performance of temperature control is crucial to the operation of isoelectric focusing equipment (IEF). In this paper, two-stage thermoelectric cooling module (TEM) is proposed to be adopted in IEF to realize prompt and precise temperature control as well as low focusing temperature (Tf). Three different prototypes including HP+baffle, AL+baffle an...

Increasing attention is being given to energy-saving air conditioning technology in recent years. Using natural refrigerant and driven by low grade thermal energy, rotary desiccant cooling system has become a sound alternative solution to conventional vapor compression system. Although one-stage ventilation rotary desiccant cooling system is still...

Composite solid desiccant materials are fabricated by impregnating hygroscopic salts into pores of different silica gels. In this paper, sorption characteristics of composite desiccants with different pore sizes (namely, 2–3 nm, 7–8 nm and 9–10 nm) of silica gels and different salts in terms of LiCl, LiBr and CaCl2 are tested and analyzed. Research...

Temperature and humidity independent control system (THIC) has become a research focus for its merits of energy saving and improved indoor thermal comfort. In this paper, a novel THIC system was experimentally investigated, which consisted of a solid desiccant heat pump (SDHP) to handle the latent load and a variable refrigerant flow (VRF) air cond...

Air source heat pump is a widely adopted system for winter heating in Central China and South China due to its high energy efficiency and low maintenance cost. However, such systems cannot produce any latent capacity resulting in decreased indoor air quality. Newly developed temperature and humidity independent control system (THIC) provides a solu...

A novel temperature and humidity independent control system (THIC) is proposed in this paper, and then experimental investigation of this system is conducted to evaluate its system performance. The THIC system is constituted of a novel solid desiccant heat pump (DESICA) to deal with the latent load and a variable refrigerant flow air conditioning s...

The method for determining the best air state point is investigated for a given cooling load and the fresh air volume. Then the relationship between the heat of adsorption of water vapor and the overall energy consumption of solid desiccant air conditioning system is discussed, finally the energy consumption of the novel air conditioning system is...

Water vaporcondensation on metal surface causes corrosion and further affects the performance. In order to decrease this disadvantageous effect, in this paper, the coating of desiccant material (silica gel) to metal surface was proposed. The performance of this method was analyzed both by experiments and by theoretical investigation. Condensation t...

Rotary desiccant wheel cooling system operates on the principle of adsorption dehumidification and evaporative cooling. The system adopts natural substance as working fluid and can be driven by low grade thermal energy such as solar energy. Due to these merits, solar powered rotary desiccant wheel cooling system has recognized as one of good altern...

The variable refrigerant flow (VRF) air conditioning system usually needs to be operated with a ventilation system, since the VRF system cannot provide fresh air. The commonly used ventilation unit with the VRF system is the heat recovery ventilation (HRV) unit due to its merits of energy saving. In this study, a novel solid desiccant heat pump uni...

In order to improve the heat transfer performance and not to influence the adsorption performance of silica gel, composite solid desiccants were fabricated by combining silica gel with Expanded Natural Graphite. Thermal conductivities and adsorption performance of these desiccants were investigated by laser flash method and dynamic weighing method,...

In this paper, an experimental setup of a desiccant dehumidification unit silica gel coated fin-tube heat exchanger is installed and investigated. In this unit, two silica gel coated heat exchangers (SCHE) are adopted and switched to provide continuous dehumidification capacity. Meanwhile, hot water from vacuum tube solar collector is used to regen...

The experimental setup of novel continuous silica gel coated heat exchanger cooling (CSCHE) system is installed and tested. In the system, two solid desiccant coated heat exchangers (SCHE) are switched forth and back to provide continuous dry and cooling air. Meanwhile, hot water from vacuum solar collector is adopted to regenerate the coated silic...

Temperature and humidity independent control (THIC) system has become an attractive alternative to conventional HVAC systems for its merits of energy-saving. In this paper, a novel solid desiccant heat pump is introduced and integrated with a conventional variable refrigerant flow air conditioning system (VRF) to form a THIC system. A standalone mo...

Solid desiccant cooling technology has become a research focus for its features of energy-saving and eco-friendly. However, widely adopted rotary desiccant wheel cooling system can't realize inner-cooling dehumidification process. In this paper, a novel self-cooled solid desiccant cooling system (SCDHE) is developed by integrating desiccant coated...

Based upon the fast development of energy efficiency, energy safety and use of renewable and sustainable energy, various energy systems related to residential refrigeration, power generation and storage have been developing. Some of them are in large scale application, while others are still under development. Current status of residential refriger...

Thermodynamic analyses of desiccant cooling cycle usually focus on the overall cycle performance in previous study. In this paper, the effects of the individual irreversible processes in each component on thermodynamic performance are analyzed in detail. The objective of this paper is to reveal the elemental features of the individual components, a...

A novel chiller with open-cycle rotary desiccant cooling has been investigated experimentally. The technologies of two-stage dehumidification and regenerative evaporative cooling have been integrated together in this chiller. The objective of this study is to extend the ability for handling sensible heat of the rotary desiccant cooling system. Base...

Experimental investigations on several commercially available and newly fabricated rotors are conducted in two different laboratories to evaluate performance trends. Experimental uncertainties are analysed and the parameters determining the rotor performance are investigated. It is found that the optimal rotation speed is lower for lithium chloride...

A novel rotary desiccant cooling cycle is proposed and studied using thermodynamic analysis method. The proposed cycle integrates the technologies of isothermal dehumidification and regenerative evaporative cooling, which are beneficial for irreversibility reduction. Thermodynamic investigation on the basic rotary desiccant cooling cycle shows that...

Solar powered solid desiccant cooling system is a good alternative to conventional vapor compression system. In this paper, a novel solar driven desiccant coated heat exchanger cooling (SDCC) system is proposed. In order to validate the feasibility of such system and to predict system performance, an integrated system model is established by combin...

In this paper, a solar hybrid desiccant air conditioning system, which combines the technologies of two-stage desiccant cooling (TSDC) and air-source vapor compression air-conditioning (VAC) together, has been configured, experimentally investigated and theoretically analyzed. The system mainly includes a TSDC unit with design cooling capacity for...

Desiccant coated heat exchanger (DCHE) system can handle latent and sensible load simultaneously by removing the released adsorption heat in dehumidification process. The system can also be driven by low grade thermal energy such as solar energy. In this paper, a dynamic one-dimensional mathematical model validated by experimental data is establish...

Ongoing research and development works suggest that good system configurations have significant potential for improving the performance and reducing the cost and size of rotary desiccant dehumidification and air conditioning system. In this paper, a novel desiccant cooling system using regenerative evaporative cooling and a one-rotor two-stage desi...

Component performance and seasonal operational experiences have been analysed for desiccant cooling systems powered by solar air collectors. Measurements during the commissioning phase in Spain (public library) and in Germany (production hall) showed that the dehumidification efficiency of the sorption rotors was 80% and the humidification efficien...

Existing desiccant cooling systems reduce the temperature of process air either by adopting evaporative coolers or incorporating vapor compression systems. While the former is restricted by inaccurate control, the latter still consumes certain quantity of electric power. To solve this problem, a thermally driven air conditioning system, which combi...

A solar thermally driven one-rotor two-stage desiccant air conditioning system, which is suitable for being used in hot humid area, has been configured. The design cooling capacity of the system is 5 kW and 15 m2 evacuated tube solar air collectors have been adopted as heat source. The system has been put into operation and its operating characteri...

In this paper, two desiccant-coated heat exchangers, which are actually fin-tube heat exchanging devices coated with silica gel and polymer materials respectively, are investigated experimentally. Due to the hygroscopic properties of the desiccant materials, both the sensible heat and the latent heat of the process air can be handled by using this...

A mathematical model for predicting the performance of novel silica gel haloid compound desiccant wheel is established. Both the gas side resistance and the solid side resistance are considered in the model. It is found that the results of this model agree better to the experiments than the results of a former model which does not take the solid si...

Solar driven rotary desiccant cooling systems have been widely recognized as alternatives to conventional vapor compression systems for their merits of energy-saving and being eco-friendly. In the previous paper, the basic performance features of desiccant wheel have been discussed. In this paper, a solar driven two-stage rotary desiccant cooling s...

In this study, a two-stage solar driven rotary desiccant cooling (TSRDC) system with novel configuration and newly developed silica gel–haloid composite desiccant is proposed aiming to reduce regeneration temperature and to achieve high energy performance. Simulated results show that there also exists an optimal rotation speed for TSRDC system. Com...

Rotary desiccant air conditioning system, which combines the technologies of desiccant dehumidification and evaporative cooling, is advantageous in being free from CFCs, using low grade thermal energy and controlling humidity and temperature separately. Compared with conventional vapor compression air conditioning system, it preserves the merits of...

Solar powered sorption cooling systems have been researched and demonstrated in recent years, which contain adsorption cooling, absorption cooling and desiccant cooling. The various typical systems with small scale for potential residential applications are discussed and analyzed, in which the working principals, system suitability for solar coolin...

The objectives of this study were to evaluate the performance of a novel two-stage rotary desiccant cooling (TSRDC) system and to obtain useful data and experiences for practical application. Newly developed compound desiccant (silica gel–haloids) was adopted in the system. An experimental set-up was built and used to test the system performance un...

A one-rotor two-stage rotary desiccant cooling system (OTSDC), in which two-stage dehumidification process is realized by one desiccant wheel, was investigated experimentally. The system was proposed to reduce the volume of two-stage rotary desiccant cooling system (TSDC) with two desiccant wheels without reduction in system performance by using th...

In the solid desiccant wheel air-conditioning system, the performance of the desiccant wheel is critical to the capability, size and cost of the whole system. Constructing mathematical model is an effective method for analyzing the performance of the rotary wheel as well as the system. The model can also be used to guide system operation, interpret...

Models of one-stage, two-stage and thick desiccant wheel systems are built and their performance are compared and analyzed using the model. The results show that two-stage desiccant wheel system is prior to the other two systems in the fields of latent heat load, sensible heat load and the whole cooling power, but its thermal performance is the low...