Performance Testing and Analysis of Silica Gel-Water Adsorption Refrigerator

Abstract In recent years, adsorption refrigeration technology has attracted wide attention from experts and scholars at home and abroad due to its environmental friendliness and energy saving advantages. In order to study the effectiveness of adsorption refrigeration technology to recover low-grade energy, a silica gel-water adsorption refrigeration system was proposed, which can effectively utilize low-grade energy such as industrial waste heat. The structure and composition of the system are introduced. The operation performance of the unit is tested under different working conditions by orthogonal experimental method, and the experimental results are analyzed. The effects of hot water temperature and flow, chilled water temperature and flow on the refrigeration capacity and COP value of the system are obtained. The experimental results show that under the low-temperature heat source of 55-75°C, the cooling capacity of the system can reach 5.3-12 and the COP value can reach 0.36-0.56. Under the same hot water temperature difference, the cooling capacity and COP value of the system increase rapidly under the condition of changing the hot water temperature at low temperature, indicating that increasing the heat source temperature at low temperature has a greater impact on the system performance. Through the analysis of primary and secondary effects, it is concluded that the inlet temperature of hot water is the main factor affecting the refrigeration capacity and COP value of the system.

Download Full-text

Experimental Study of a Laminar Flow Solid Desiccant Dehumidifier Driven by a Low Temperature Heat Source

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.819.361 ◽

2016 ◽

Vol 819 ◽

pp. 361-365 ◽

Cited By ~ 1

Author(s):

Seung Jin Oh ◽

Kyaw Thu ◽

Muhammad Wakil Shahzad ◽

Wongee Chun ◽

Kim Choon Ng

Keyword(s):

Experimental Study ◽

Low Temperature ◽

Laminar Flow ◽

Heat Source ◽

Silica Gel ◽

Average Diameter ◽

Hot Water ◽

Dry Air ◽

Temperature Heat ◽

Adsorption Desorption

In this paper, an experimental study of a laminar flow solid desiccant dehumidifier has been presented. The cyclic steady state performance of adsorption-desorption processes was analyzed at various heat source temperatures and typical ambient humidity conditions in tropics. The desiccant dehumidification system consists of two beds filled with silica gel, two heat exchangers operating at 30 oC and 80 oC respectively, three humidity stations for measurement of the temperature and humidity conditions of the system and a blower to make airflow throughout the system. Type-RD silica gel of 0.3 mm average diameter was used as the working desiccant in the dehumidification system. This system has no moving parts rendering less maintenance compared with a rotary type. It is also energy-efficient means of dehumidification by adsorption process with low temperature heat source as compared to the conventional methods. As a result, it was observed the humidity ratio of inlet air is reduced from 24 g/kg of dry air to about 17 g/kg of dry air. Concomitantly, hot water at 80 oC is used to regenerate the adsorbent.

Download Full-text

Two-Stage Non-Regenerative Silica Gel-Water Adsorption Refrigeration Cycle

10.1115/imece2000-1297 ◽

2000 ◽

Author(s):

B. B. Saha ◽

K. C. A. Alam ◽

A. Akisawa ◽

T. Kashiwagi ◽

K. C. Ng ◽

...

Keyword(s):

Heat Pump ◽

Silica Gel ◽

Water Adsorption ◽

Waste Heat ◽

Cooling Capacity ◽

Coefficient Of Performance ◽

Adsorption Refrigeration ◽

Two Stage ◽

Adsorption Chiller ◽

Adsorption Heat Pump

Abstract Over the past two decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Closed-type, conventional adsorption refrigeration and heat pump systems have an increasing market share in Japan. In this paper, a two-stage non-regenerative, silica gel-water adsorption chiller design is outlined. Experimental measurements are performed on a prototype of a 3.5 kW rated cooling capacity adsorption heat pump in order to determine its performance under different operating temperatures (hot, cooling and chilled water). The chiller performance is analyzed in terms of cooling capacity and coefficient of performance (COP). The main innovative feature in the two-stage adsorption chiller is the ability to utilize low-temperature waste heat (∼55°C) as the driving source with a cooling source of 30°C. The technological difficulty inherent in operating a thermally activated cycle with such a small regenerating temperature lift (temperature difference between heat source and heat sink inlets) is overcome by use of a two-stage cycle.

Download Full-text

Performance Investigation of a Two-Bed Type Adsorption Chiller with Various Adsorbents

Energies ◽

10.3390/en13102553 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2553 ◽

Cited By ~ 1

Author(s):

Jung-Gil Lee ◽

Kyung Jin Bae ◽

Oh Kyung Kwon

Keyword(s):

Performance Evaluation ◽

Physical Properties ◽

Water Temperature ◽

Silica Gel ◽

System Performance ◽

Waste Heat ◽

Sustainable Energy ◽

Cooling Capacity ◽

Hot Water ◽

Adsorption Chiller

In this study, the performance evaluation of an adsorption chiller (AD) system with three different adsorbents—silica-gel, aluminum fumarate, and FAM-Z01—was conducted to investigate the effects of adsorption isotherms and physical properties on the system’s performance. In addition, the performance evaluation of the AD system for a low inlet hot-water temperature of 60 °C was performed to estimate the performance of the system when operated by low quality waste heat or sustainable energy sources. For the simulation work, a two-bed type AD system is considered, and silica-gel, metal organic frameworks (MOFs), and ferro-aluminophosphate (FAPO, FAM-Z01) were employed as adsorbents. The simulation results were well matched with the laboratory-scale experimental results and the maximum coefficient of performance (COP) difference was 7%. The cooling capacity and COP of the AD system were investigated at different operating conditions to discuss the influences of the adsorbents on the system performance. Through this study, the excellence of the adsorbent, which has an S-shaped isotherm graph, was presented. In addition, the influences of the physical properties of the adsorbent were also discussed with reference to the system performance. Among the three different adsorbents employed in the AD system, the FAM-Z01 shows the best performance at inlet hot water temperature of 60 °C, which can be obtained from waste heat or sustainable energy, where the cooling capacity and COP were 5.13 kW and 0.47, respectively.

Download Full-text

Development and comparison of two-bed silica gel–water adsorption chillers driven by low-grade heat source

International Journal of Thermal Sciences ◽

10.1016/j.ijthermalsci.2008.07.004 ◽

2009 ◽

Vol 48 (5) ◽

pp. 1017-1025 ◽

Cited By ~ 21

Author(s):

Z.Z. Xia ◽

R.Z. Wang ◽

D.C. Wang ◽

Y.L. Liu ◽

J.Y. Wu ◽

...

Keyword(s):

Heat Source ◽

Silica Gel ◽

Water Adsorption ◽

Low Grade ◽

Low Grade Heat

Download Full-text

Experimental Implementation of a Micro-Scale ORC-Based CHP Energy System for Domestic Applications

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change, Parts A and B ◽

10.1115/imece2010-37208 ◽

2010 ◽

Cited By ~ 8

Author(s):

Massimo Malavolta ◽

Asfaw Beyene ◽

Mauro Venturini

Keyword(s):

Low Temperature ◽

Heat Source ◽

Hot Water ◽

Economic Viability ◽

Small Scale ◽

Low Grade ◽

Micro Scale ◽

Exhaust Heat ◽

Domestic Use ◽

Low Grade Heat

Because of the renewed interest in renewable energy as well as increased emphasis on alternative technologies, micropower-generating systems have attracted considerable research interest over the last decade. However, micro-scale power generation for low grade heat recovery applications, i.e. as low as 1–3 kW - for domestic use, are characterized by very low efficiencies and relatively high specific cost. For economic viability, these factors make it imperative that the heat source remains “free”, such as solar or geothermal energy. In this paper, a small-scale Organic Rankine Cycle (ORC) is presented. The small-scale ORC module was built and tested at San Diego State University lab, aimed at producing electricity and hot water from ultra-low grade heat source that can be tapped from solar collectors and low temperature exhaust heat. The system was built for economic viability and flexibility, tailored for a domestic use. The tests demonstrated that the system offered CHP capability, with electric and thermal power output suitable for a domestic application. It also offered high operational flexibility, since the scroll expander could work with a high temperature range, accommodating an even-significant drop of the heat source temperature. Therefore, it can be conveniently used to capture solar and low-temperature energy sources. The system could be produced at an overall cost of less than $3,000 (USD 2010).

Download Full-text

Quantitative and Qualitative Comparison of Low-Temperature, Heat-Activated Cooling Systems

Advanced Energy Systems ◽

10.1115/imece2006-14489 ◽

2006 ◽

Author(s):

Y. Gupta ◽

L. Metchop ◽

T. Frantzis ◽

P. E. Phelan

Keyword(s):

Heat Transfer ◽

Heat Source ◽

Silica Gel ◽

Hot Water ◽

Absorption System ◽

Qualitative Comparison ◽

Cooling Systems ◽

Source Temperature ◽

Air System ◽

Refrigeration Capacity

This paper compares the quantitative and qualitative performances of three different heat-activated cooling systems, e.g. a silica-gel water adsorption system, a LiBr-H2O absorption system, and a desiccant air system. Each of these systems can be utilized at relatively low heat source temperatures, but it is unclear which of these systems is best suited to what range of heat source temperature. Our study explores answers to this question by generating quantitative results comparing their relative thermal performance, i.e. COP and refrigeration capacity, and a qualitative comparison based on the size, maturity of technology, safe operation, etc. Each of these systems is assumed to work under the following operating conditions: a condensing temperature of 29 °C, an evaporating temperature of 19 °C, a hot water temperature range of 40-120 °C, and a hot water mass flow rate of 0.4 kg/sec. Individual mathematical models are developed for each system and numerically solved using different techniques. In order to provide a fair comparison between the fundamentally different systems, a UA (overall heat transfer coefficient multiplied by the heat transfer area) value of 1.0 kW/ °C is considered for the heat exchanger that transfers heat from the supplied hot water. Furthermore, to compare systems of similar size, the mass of silica gel in adsorption and desiccant system and mass of LiBr-H2O solution in absorption system were specified such that each system provides the same amount of refrigeration (8.0 kW) at a source temperature of 90 °C. It is found that the absorption and adsorption cooling systems have a higher refrigeration capacity at heat source temperatures below 90 °C, while the desiccant air system outperforms the others at temperatures above 90 °C.

Download Full-text

Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC

Archives of Thermodynamics ◽

10.2478/v10173-011-0013-5 ◽

2011 ◽

Vol 32 (3) ◽

pp. 57-70 ◽

Cited By ~ 2

Author(s):

Dariusz Mikielewicz ◽

Jarosław Mikielewicz

Keyword(s):

Power Plant ◽

Low Temperature ◽

Heat Source ◽

Silicone Oil ◽

Hot Water ◽

Working Fluid ◽

Preliminary Heating ◽

Source Temperature ◽

Heat Source Temperature ◽

Steam Heat

Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC In the paper presented is a novel concept to utilize the heat from the turbine bleed to improve the quality of working fluid vapour in the bottoming organic Rankine cycle (ORC). That is a completely novel solution in the literature, which contributes to the increase of ORC efficiency and the overall efficiency of the combined system of the power plant and ORC plant. Calculations have been accomplished for the case when available is a flow rate of low enthalpy hot water at a temperature of 90 °C, which is used for preliminary heating of the working fluid. That hot water is obtained as a result of conversion of exhaust gases in the power plant to the energy of hot water. Then the working fluid is further heated by the bleed steam to reach 120 °C. Such vapour is subsequently directed to the turbine. In the paper 5 possible working fluids were examined, namely R134a, MM, MDM, toluene and ethanol. Only under conditions of 120 °C/40 °C the silicone oil MM showed the best performance, in all other cases the ethanol proved to be best performing fluid of all. Results are compared with the "stand alone" ORC module showing its superiority.

Download Full-text