Energy Fuels 2009, 23, 5677–5683 Published on Web 09/02/2009
: DOI:10.1021/ef900523f
Cooling Performance of a Combined Solar Thermoelectric-Adsorption Cooling System: An Experimental Study M. O. Abdullah,* J. L. Ngui, K. Abd. Hamid, S. L. Leo, and S. H. Tie Faculty of Engineering, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia Received May 25, 2009. Revised Manuscript Received August 20, 2009
A novel solar thermoelectric-adsorption cooling system was built and tested at eight different days. Cooling is produced via the Peltier effect during the day, by means of thermoelectric elements, and through adsorption process at night. The coefficient of performance (COP) values were determined using derived equations, the average COP values of the overall system are ∼0.131 (adsorption) and ∼0.152 (thermoelectric), respectively. 1. Introduction Adsorption and thermoelectric cooling systems are some of the cooling systems available around the globe. Solar adsorption cooling system has witnessed an increasing interest in many fields, because of it is quiet, long-lasting, inexpensive to maintain, and environmentally benign.1,2 However, solar thermoelectric cooling utilizes the conversion of solar energy to electricity energy by means of photovoltaic cells to power up the cooler. Pons and Guilleminot3 developed an icemaker based on the solar-powered adsorption system with activated carbonmethanol as the working pair. The coefficient of performance (COP) of 0.12 was achieved with a production of 6 kilograms of ice per square meter of solar collector/adsorber. Liu et al.,4 on the other hand, developed an adsorption chiller with the working pair of silica gel-water, powered by a solar water heater. A cooling power of 3.56 kW and a COP value of 0.26 are obtained with their prototype. Khattab and El Shenawy5 utilized thermoelectric cooling for their simulation study, using a small thermoelectric generator powered by waste heat or solar heat to drive a small thermoelectric cooler. The thermoelectric generator consists of 49 thermocouples, and the thermoelectric cooler contains 127 thermocouples. From their findings, 5 thermocouples of the thermoelectric generator can drive 1 thermocouple of the thermoelectric cooler. For optimum performance, 10 thermoelectric generator modules are required to power 1 thermoelectric cooler most times of the year. However, an experimental study has been conducted by Abdul-Wahab et al.6 on a solar
Figure 1. Estimated adsorption quantity of refrigerant in the activated carbon versus saturated refrigerant temperature, at three different adsorption temperatures of activated carbon.
*Author to whom correspondence should be addressed. Tel.: þ60 82 583280 (direct line). Fax: þ 082-583409. E-mail addresses:
[email protected],
[email protected]. (1) Dieng, A. O.; Wang, R. Z. Renew. Sustain. Energy Rev. 2001, 5, 313–342. (2) Abdullah, M. O.; Leo, S. L. In Proceedings of ASME/ISEC2005, International Solar Energy Conference, Orlando, FL, August 6-12, 2005. (CD-ROM). (3) Pons, M.; Guilleminot, J. J. J. Sol. Energy;Trans. ASME 1986, 108 (4), 332–7. (4) Liu, Y. L.; Wang, R. Z.; Xia, Z. Z. Int. J. Refrig. 2005, 28 (2), 218– 30. (5) Khattab, N. M.; El Shenawy, E. T. Energy Convers. Manage. 2006, 47, 407–426. (6) Abdul-Wahab, S. A.; Elkamel, A.; Al-Damkhi, A. M.; Al-Habsi, I. A.; Al-Rubai’ey, H. S.; Al-Battashi, A. K.; Al-Tamimi, A. R.; AlMamari, K. H.; Chutani, M. U. Renew. Energy 2009, 34, 30–34. r 2009 American Chemical Society
Figure 2. Hybrid solar thermoelectric-adsorption cooling system (front view).
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pubs.acs.org/EF
Energy Fuels 2009, 23, 5677–5683
: DOI:10.1021/ef900523f
Abdullah et al.
Figure 3. Hybrid solar thermoelectric-adsorption cooling system (back view).
Figure 4. Location of valves in the adsorption cooling system.
Figure 5. Schematic diagram of the adsorption cooling system.
Figure 6. Schematic diagram of the thermoelectric cooling system.
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Energy Fuels 2009, 23, 5677–5683
: DOI:10.1021/ef900523f
Abdullah et al.
Table 1. Properties of Coconut-Based Activated Carbona parameter
value/comment
base material particular shape bulk density moisture content ball-pan hardness ash content carbon tetrachloride activity iodine number methylene Blue benzene absorption surface area (BET-m2/g) pore volume pH value mesh size
coconut shell charcoal granular 0.48-0.49 g/mL
