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Intermittent Absorption Refrigeration

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International Journal of Energy Research  26 (9): 825 - 835 (2002)

Operational Results of an Intermittent Absorption Cooling Unit
Ali R. El-Ghalban *

Department of Mechanical Power Engineering, Faculty of Engineering, Menufia University, Shebin El-kaum, Egypt
email: Ali R. El-Ghalban (aghalban@hotmail.com)
Correspondence to Ali R. El-Ghalban, Department of Mechanical Power Engineering, Faculty of Engineering, Menufia University, Shebin El-Kaum, Egypt

The concept of solar cooling is appealing because the cooling load is in phase with the intensity of solar energy. Many system arrangements or cycles are employed to achieve solar cooling, such as Absorption, desiccant or Rankine-vapour compression systems. The technical feasibility of driving an absorption-cooling unit by a low-temperature heat source (such as solar energy using a simple flat-plate collector) for air-conditioning applications is investigated in this work.

This study aims to design and construct a prototype for an intermittent absorption refrigeration system and to examine its implementation. The operating characteristics of the considered unit are extensively investigated. In order to accomplish this strategy, the prototype was integrated in a test rig designed for this purpose and equipped with the necessary measuring instruments to determine the required operating criteria of the unit. The energy added or extracted to or from the different unit components is calculated and the system performance is analysed.

The C.O.P of the unit is found to be 19% which is 2% lower than the designed value, which could be regarded as an encouraging result for more studies in this field. Copyright © 2002 John Wiley & Sons, Ltd.


http://igi.uni.edu.pe/indextecnia/02-9-2.htm

EVALUACIÓN Y DISEÑO PRELIMINAR DE UN PROTOTIPO EXPERIMENTAL DE REFRIGERACIÓN POR ADSORCIÓN

Miguel Ramos, Manfred Horn, Rafael Espinoza
Centro de Energías Renovables y Uso Racional de la Energía
E-mail: mramos@uni.edu.pe/ cer@uni.edu.pe

Abstract --- This paper presents some of the experimental evaluations of a prototype solar refrigerator, based on an intermitent thermodynamic cyele of adsorption, using water as refrigerator and the mineral zeolithe as adsorber: The objective is to analyse the advantages and disadvantages of the eventual use in rural regions of Peru. On the bases of the results obtained, a new prototype of refrigerator for rural regions is designed, based on the same thermodynamic cyele...including changes in design and operarían.


Renewable Energy 6 (7) 867-882 (October, 1995)

Adaptation of an adsorptive solar refrigerator to Moroccan climates

Bentayeb, F.a; Lemmini, F.a; Guilleminot, J. J.b

a. Laboratoire d'Energie Solaire, Faculté des Sciences, B.P. 1014, Rabat, Morocco
b. LIMSI CNRS, B.P. 30, 91406 Orsay, France

In this paper, we introduce a model taking account of the real operation of an adsorptive solar refrigerator using activated carbon-methanol pairs, as a function of the climatic conditions: ambient temperature and insolation. The model is used to simulate the operation of the refrigerator in two Moroccan climates: Rabat, temperate and humid, and Marrakech, dry and hot. The numerical simulation shows that the behaviour of the refrigerator is different from one climate to the other. In Rabat, which has a Mediterranean climate, the cold room temperature can be maintained at a value practically always less than 5°C; whereas in Marrakech, which has a pre-Saharan climate, an overheating problem can arise in the summer season and temperatures in the cold room can reach 17°C. Results also show that in both climates we are confronted with the problem of freezing because the cold room temperatures can be less than 0°C and reach -15°C in the winter.

Elsevier Science
Item: 0960-1481(94)E0020-6
ISSN: 0960-1481


Solar Energy  60 (2): 77-87 (February, 1997)

Design optimization of the flat plate collector for a solid absorption solar refrigerator

Enibe, S. O.a; Iloeje, O. C.a

a. National Centre for Energy Research and Development and Department of Mechanical Engineering, University of Nigeria, Nsukka, Nigeria

A study of the effects of various collector design parameters on the performance of a solar powered solid absorption refrigerator is presented. The refrigerator uses specially treated CaCl2 as absorbent and NH3 as refrigerant and operates intermittently in a diurnal cycle. The study is undertaken using version 4.0 of a simulation programme, COSSOR, developed from a transient analysis of the system. A large number of simulations was undertaken to test the performance of the refrigerator for various choices of the collector design parameters. The latter include the plate emissivity and material; absorbent pellet diameter, thermal conductivity and packing density; collector tube size, spacing and material; and number of glazing. The refrigerator performance indicators, namely total condensate yield, mass of ice produced, coefficient of performance and effective cooling, are presented for the range of values of the collector parameters of interest. Using a multiple linear regression technique, the performance indicators are correlated with the collector parameters by simple linear polynomial expressions. An objective function, suitable for selecting optimal values of the parameters, is defined, subject to specified constraints. Optimization was then carried out for the objective function. For the collector with steel tubes and steel plate, the refrigerator coefficient of performance obtained with optimal choices of tube size, spacing and plate emissivity is 0.073, representing an improvement of at least 30% with respect to the reference collector. A similar level of improvement was obtained for a collector with aluminium tubes and plate.


http://www.ulb.ac.be/ceese/STAFF/safonov/ISEERC2001/Abstract/Vasiliev_et_al.htm

Solar/gas sorption heat pumps and refrigerators-nature friendly heat transport systems

L.L. Vasiliev, D.A.Mishkinis, A.A. Antukh, L.L. Vasiliev Jr.
Luikov Heat & Mass Transfer Institute, National Academy of Sciences, Minsk, Belarus.

An advanced active carbon fiber(salts) /NH3 heat pumps and refrigerators with dual sources of energy (solar/gas, solar/electricity) are considered for providing space heating, cooling and sanitary hot water for buildings. The high temperature sources of the energy are solar and gas/electricity. The low temperature sources of energy are - the ground water, soil, and air. The new refrigerators and heat pumps generation includes combination of chemicals with an active carbon fiber to increase NH3 sorption capacity. The general goal of this paper is to present the results of an investigation of a new environmentally friendly thermal machines. In these designes a physical adsorption and chemical reactions are used simultaneously for a heat and cold generation. A solar refrigerator and heat pump is made of a solar collector, absorbed natural gas vessel (ANG), and compact, portable heating/refrigeration system, which consists of two small adsorbers with heat pipe heat recovery system.


Energy Conversion and Management 44 (2): 301-312 (January 2003)

Review of solid adsorption solar refrigerator I: an overview of the refrigeration cycle

E. E. Anyanwu

el.: +234-83-230-974; email: eanyanwu@futo.edu.ng
Department of Mechanical Engineering, Federal University of Technology, P.M.B. 1526, Owerri, Imo State, Nigeria

 
Abstract --- A review of the practically realized solid adsorption solar refrigeration cycles is presented. The cycles also have potentials for use as heat pumps. They have been classified according to the adsorbate utilized as: cycles with water as refrigerant, cycles using fluorocarbon as refrigerant, cycles using ammonia as refrigerant and cycles with alcohols as refrigerant. The performances of these refrigeration cycles, drawn from experiences worldwide, are also reported. The actual field testing experiences, together with the technical and economic constraints that affect popularization of the systems are reviewed, and their possible solutions are suggested.


Small Power Systems
74550 Dobie Lane
Covelo, CA 95428

Call: 800-972-7179
FAX: 707-983-6525
Email: SPS@pacific.net

Solar Absorption Refrigerator

Small Power Systems has developed a non-electric solar refrigerator-freezer. The refrigerator uses an aqua-ammonia absorption system similar to that used in propane refrigerators. The refrigerator consists of two separate units; the solar collector-generator and the refrigerator box.

The collector-generator consists of a thermal solar collector and most of the refrigeration works. It measures about 5' x 4'x 1' and weighs over 100 lbs. It needs to be mounted in a sunny location, the same as any solar collector.

The refrigerator box is the refrigerator per se and can be placed wherever is convenient, presumably the kitchen.

When the sun shines, the collector-generator produces ammonia refrigerant which is stored until night when the actual cooling takes place. To keep the refrigerator cold through the day and during cloudy weather, there is built-in storage sufficient for five days. There are no moving parts.

In use, our solar refrigerator is little different from any other refrigerator. It even has automatic defrost. Currently, the drawbacks are slightly higher freezer temperatures and a greater temperature variation since there is only one cycle per day.

We are currently building a very limited number of these refrigerators for customers who are willing to work with us on the design and put up with the idiosyncrasies of our current work. We do not currently have a date when we might have refrigerators in quantity. The interest in these refrigerators has exceeded our expectations and we are wondering on what scale to proceed. The cost is also an unknown, but roughly the cost of a Sunfrost not counting installation is an estimate.

The current plan is to build units 30" wide and 48" and 70" tall. We are also prototyping a very small unit where the refrigerator box is under the solar collector so it is all one unit that is left outside. This is meant to be used for vaccines and to be as low cost and simple as possible. We do not plan to include a freezer except limited ice-making capacity, as this simplifies the design. This may be the first model to be generally available.

Since there has been a lot of interest in North America which wasn't our original design area, we have been looking seriously at auxiliary cooling for prolonged cloudy spells. We are trying an external heat pipe for colder locations and thermoelectric cooling for warmer locations. These have the advantage of being relatively inexpensive and can be offered as add-ons instead of requiring extensive redesigning. Even though propane is a natural, it seems too difficult to implement at present.

We are also considering two technologies which would add to the expense but make a better product. Even though Owens Corning has canceled their Aura vacuum panel insulation production, others are working on similar products. The advantage is better insulation and thinner walls, resulting in a smaller cabinet. The disadvantages are higher cost and no guarantees that the product will be able to hold its vacuum for extended time. Guarantees with most products are under 5 years at present.

The other technology we are considering is keeping the cold storage outside at the solar collector and using a pump to circulate the cold into the refrigerator. This would add significantly to the expense and require electricity, but would simplify installation and keep ammonia out of the living space.

We feel that safety, particularly in transportation and installation is a significant issue that needs to be thoroughly looked into before we can offer these refrigerators to the general public, and this will take time.


Some Recommended Links to Intermittent Absorption Refrigeration:

http://www.mmsunshine4.freeserve.co.uk/ebmip/n1.htm
http://rcl.eng.ohio-state.edu/~christ-r/ceat/theory/theory.html
http://www.linkhoek.nl/industrie/absorption-refrigeration.html


Patents

US Patent # 5,272,891 ~ Intermittent Sorption Cycle with Integral Thermosyphon

US Patent # 4,966,014 ~ Solar Absorption Refrigeration

US Patent # 4,744,224 ~ Intermittent Solar Ammonia Absorption Cycle Refrigerator

US Patent # 4,623,018 ~ Thermal System based on Thermally Coupled Intermittent Absorption Heat Pump Cycles

US Patent # 3,585,810 ~ Intermittent Absorption Refrigerating Machine

US Patent # 2,622,413 ~ Refrigerating Apparatus of the Intermittent Absorption Type

US Patent # 2,513,148 ~ Intermittent Absorption Refrigeration

US Patent # 2,487,861 ~ Intermittent Absorption Refrigeration Apparatus

US Patent # 2,438,105 ~ Refrigerating Apparatus of the Intermittent Absorption or Adsorption type

US Patent # 2,435,107 ~ Two Temperature Intermittent Type Absorption Refrigerator

US Patent # 2,401,233 ~ Intermittent Absorption or Adsorption Type Refrigeration

US Patent # 2,393,241 ~ Intermittent Absorption or Adsorption Refrigerating Apparatus

US Patent # 2,370,643 ~ Refrigeration Apparatus of the Intermittent Absorption or Adsorption Type

US Patent # 2,138,686 ~ Intermittent Absorption Refrigerating Apparatus

US Patent # 2,045,054 ~ Intermittent Absorption Refrigerating System

US Patent # 2,001,143 ~ Intermittent Absorption Refrigerating Apparatus

US Patent # 2,001,142 ~ Intermittent Absorption Refrigerating Apparatus and Method

US Patent # 1,991,271 ~ Automatic Control for Intermittent Absorption Refrigeration Apparatus

US Patent # 1,936,039 ~ Intermittent Absorption Refrigerating System

US Patent # 1,918,969 ~ Automatic Control for Intermittent Absorption Refrigeration Apparatus

US Patent # 1,914,687 ~ Liquid Return for Intermittent Absorption Refrigerators

US Patent # 1,898,616 ~ Generator-Absorber for Intermittent Absorption Refrigerators

US Patent # 1,861,075 ~ Intermittent Absorption Refrigerating Apparatus

US Patent # 1,811,523 ~ Intermittent Absorption Refrigerating Apparatus (Icy-Ball)

US Patent # 1,779,070 ~ Intermittent Absorption Refrigeration Apparatus

US Patent # 1,740,737 ~ Intermittent Absorption Refrigerating Apparatus (Icy-Ball)

US Patent # 1,718,690 ~ Intermittent Absorption Refrigerating Apparatus

US Patent # 1,707,892 ~ Refrigeration Plant of the Intermittent Absorption Type

US Patent # 1,632,701 ~ Intermittent Absorption Refrigerating System

US Patent # 1,376,884 ~ System of Control for Intermittent Absorption Refrigerating Plants


Foreign Patents ~

GB (Great Britain) Patent # 229,702 ~ Refrigerating machine of the absorption type
GB Patent # 462,072 ~ Improvements relating to intermittent dry-absorption refrigeration
GB Patent # 459,974 ~ Improvements relating to intermittent dry-absorption refrigerating systems and apparatus
GB Patent # 453,827 ~ Improvements in or relating to intermittently acting absorption refrigerating apparatus
GB Patent # 451,253 ~ Improvements in intermittently acting absorption refrigerating apparatus
GB Patent # 447,399 ~ Improvements in or relating to intermittently acting absorption refrigerating apparatus
GB Patent # 447,398 ~ Improvements in or relating to intermittently acting absorption refrigerating apparatus
GB Patent # 445,692 ~ Improvements in or relating to intermittently acting absorption refrigerating apparatus
GB Patent # 438,959 ~ Improvements in or relating to absorption refrigerating apparatus
GB Patent # 437,370 ~ Improvements in or relating to absorption refrigerating apparatus of the intermittent type
GB Patent # 431,268 ~ Improvements in or relating to absorption refrigerating apparatus
GB Patent # 431,267 ~ Improvements in or relating to absorption refrigerating apparatus
GB Patent # 417,111 ~ Improvements in and relating to intermittent absorption refrigerating apparatus
GB Patent # 417,040 ~ Improvements in and relating to intermittent absorption refrigerating apparatus
GB Patent # 415,488 ~ Refrigeration process and apparatus
GB Patent # 409,493 ~ Improvements in or relating to cooling systems for intermittently acting absorption refrigerating apparatus
GB Patent # 389,077 ~ Absorption refrigerating apparatus
GB Patent # 359,064 ~ Improved method of, and means for refrigeration
GB Patent # 311,324 ~ Refrigeration plant of the intermittent absorption or adsorption type
GB Patent # 310,739 ~ Improvements relating to intermittent absorption refrigerating apparatus
GB Patent # 292,556 ~ Improvements in and relating to the regulation of continuous cycle absorption refrigerating machines
GB Patent # 578,967 ~ Improvements in or relating to absorption refrigerating apparatus
GB Patent # 523,732 ~ Improved method of, and means for refrigeration
GB Patent # 520,978 ~ Intermittent absorption refrigerating apparatus without valves
GB Patent # 511,230 ~ Improvements in or relating to absorption refrigerating systems and apparatus
GB Patent # 500,002 ~ Improvements in and relating to intermittent absorption refrigerating apparatus
GB Patent # 492,724 ~ Improvements in or relating to heat transfer systems
GB Patent # 483,476 ~ Improvements in or relating to the heating of absorption refrigerating apparatus
GB Patent # 480,018 ~ Improvements in and relating to intermittent absorption refrigerating machines
GB Patent # 468,651 ~ Method of and apparatus for absorption refrigeration
GB Patent # 467,449 ~ Improvements in or relating to absorption type refrigerating apparatus
GB Patent # 466,530 ~ Condenser units for absorption refrigerating machines
GB Patent # 730,507 ~ An intermittent absorption refrigerating system for use in vehicles
GB Patent # 612,112 ~ Improvements in or relating to intermittent reversible absorption refrigerating apparatus
GB Patent # 995,631 ~ A device in furnaces delivering hot gases for cooling the gases and utilizing their heat content
GB Patent # 2,213,244 ~ Refrigerating appliances
GB Patent # 1,188,626 ~ No English title available.
GB Patent # 1,178,023 ~ No English title available.

WO 8901119 ~ Intermittent Solar Ammonia Absorption Cycle Refrigerator
WO 8600691 ~ Heat Exchange Device Usable as a Solar Refrigerator with Intermittent Absorption

EP 0374179 ~ Intermittent Solar Ammonia Absorption Cycle Refrigerator
EP 0203558 ~ Apparatus for and method of water heating by an intermittent adsorption process.
EP 0187794 ~ HeatExchange Device Usable as a Solar Refrigerator with Intermittent Absorption
EP 0131869 ~ Thermal system based on thermally coupled intermittent absorption heat pump cycles.

JP 61038367 ~ Solar-Heat Driving Intermittent Type Absorption Refrigerator
JP 61036663 ~ Regenerator for Solar-Heat Driving Intermittent Type Absorption Refrigerator
JP 60223975 ~ Solar-Heat Driving Intermittent Type Absorption Refrigerator
JP 60196566 ~ Solar-Heat Driving Intermittent Type Absorption Refrigerator

AU 604565 ~ Intermittent Solar Ammonia Absorption Cycle Refrigerator
AU 2309588 ~ Intermittent Solar Ammonia Absorption Cycle Refrigerator

HU 176591 ~ Intermittnet Absorption Cooler for Making Ice

FR 2567253 ~ No English title available.

DK 101186 ~ Heat exchanger apparatus for use as a solar refrigerator with intermittent absorption

OA 9161 ~ Intermittent solar ammonia absorption cycle refrigerator

CN 1362605 ~ Absorption-type refrigerating method and refrigerator




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