Space heating and cooling
Simulation 97103216 cooling system
of a double-effect
Wardono, B. and Nelson, R. ASHRAE J., October 1996, 38, (10) 32-38. A simulated double-effect lithium bromide/water absorption system was investigated. The main energy input was hot water. System optimization is proved to he possible in the light of the results and there is an added economic optimum heat transfer area for each hear exchanger and a glohal minimum cost of the system.
Single and multi indoor unit and light commercial applications
Colombo, G and Casale, C. Con&z. dell ‘Aria, September 1996, 10321045. (In ttaiian) States that small capacity split systems are ideal solutions for single room air conditioning in dwellings for many practical reasons. Deals with the various configurations of indoor units as well as outdoor condensing units, the technology used in the refrigeration systems, air movement, noise control and electronics. Includes a comparison of all types and also discusses chilled water versions and multi unit systems. Presents trends and future developments.
Six steps to follow that ensure 97193218 tion system design and control Morton,
1996, 102. Part2, SA-96-10-3,
Solar powered combined ejector vapour 97103219 sion cycle for air conditioning and refrigeration
Sun, D.-W. Energy Comers. Mgmt, 1997, 38, (5), 479-491. Electric energy generally powers the refrigeration and air conditioning that provide human comfort, food processing and storage and many other industrial processes. On the other hand, solar energy is widely available and has no fuel cost, which makes the running of solar powered refrigeration a viable and economic proposition. Unfortunately, research shows that solar powered conventional refrigeration systems have a relatively low coefficient of performance (COP). This paper describes a new way for harnessing solar energy, using a combined ejector vapour compression cycle. This combined cycle brings together the advantages and eliminates the disadvantages of the two common conventional cycles. The study shows that the combined cycle is: (i) a potentially high performance system with a potential increase in system COP by more than 50% over the conventional cycles; (ii) a ‘green’ system that conforms to all foreseeable ozone preserving regulations and reduces ‘green house’ effects; and (iii) a cost-effective system with low maintenance.
97103220 Statistical eration units
Yami-Qiao, J. and Shi-Liang. W. 1nt.J. Refiig., July 1996, 19, (h), 407-413. The container refrigeration units used in marine transportation were studied to determine the reliability characteristics. Data from 4318 refrigeration containers of a shipping company studied over four years’ shipping time are reported. Reliability characteristics for four principal types of container refrigeration units were observed-Daikin, Paul Klinge, Mitsubishi and Carrier.
Austin-Davies J. er al. Air Condit. Refrig. News, November 1996, 13, (2), 30-45. Some of the changes that have taken place over the last 20 years are reported, with a description of a fully integrated HVAC, refrigeration and lighting control system at a Waitrose supermarket. Equipment and recent installations in the UK are detailed.
Survey of design considerations 97103222 air conditioning systems in Hong Kong
Chow, W. K. and Fung, W. Y. ASHRAE Trans., 1996, 102, part 2, (4002), 210-219. Ventilation and air conditioning systems design in Hong Kong were studied. Information on the primary design objectives, design guides, criteria selected, etc., was collected through questionnaires distributed to building services engineering consultants, contractors and operation firms. The design tools used are also assessed. The authors conclude that air distribution system design may require improved methods.
97103223 Thermal performance of a tapered store containing tubes of phase change material: cooling cycle Kiirklii, A. Energy Convers. Mgmt,1997, 38, (4), 333-340. The author investigates the thermal performance of a tapered store, including constant cross-section phase change material (PCM) tubes. Three different air-flow rates and four different air inlet temperatures were used in the tests. The results showed that the cycle time was shortened as the air inlet temperature was decreased. The same effect was obtained when the air-flow rate was increased. An even temperature distribution was observed at the centre position within the PCM along the tubes. This was a consequence of increasing the air velocity along the store. Heat transfer rates along the store were found to he close to each other. The average effectiveness of the store was found to be around 44%.
Fuel and Energy Abstracts
Kruse, H. rr al. Ki Luft. Kalferechi., November 199h. 32. (I I). 4Y6-500. The binary and ternary mixtures of the refrigerants R32, R/25. RIJ30, and RI340 as ozone-friendly substitutes for R22. R502 and RJ3BJ are discussed. Studies were carried out to examine the thermal hehaviour of these mixtures in two of four projects of a joint investigation. The result\ arc presented and discussed.
Two-axis goniometer 97103225 of a dilution refrigerator
for use in the mixing chamber
Suzuki, M. Clyogenicv, 1997. 37, (5). 275-277. A goniometer has been constructed to rotate a sample around two independent axes in the mixing chamber of a dilution refrigerator. The goniometer was designed to investigate the angular dependence of the magnetic de Haaa-van Alphen effect of heavy electron material\ in a magnetic field of up to 14.5 T.
A two-dimensional numerical investigation of the 97103226 optimal removal time and entropy reduction rate for a sensible thermal storage system. Maveety, J. G. and Razani, A. Energy Jnr. J., lYY6, ?I, (12) 1265-1276. Two-dimensional transient effects of a cylindrical. sensible energy-storage system are considered as an extension of a previous one-dimensional analytical study. The working fluid NaK is assumed to he incompressible. Conduction in the annulus and convection to the working fluid accounts for the energy transfer from the high temperature surrounding domain. Second law aspects of the two subsystems are also examined and the paper isolates irreversihilities which reduce the availability.
97103227 U.S. Naval Academy serving as energy showcase
Chiu, C. Y. Dixrr. Energy, 1996, 82, (2), 27-31. The first true district heating system in the United States wa\ huilt hy the U.S. Naval academy in 1853. The systems on display are described, with new advanced technologies in energy and water conservation.
Utilizing 97103228 ing load calculations
Al-Rabghi, 0. M. A. and Al-Johani, K. M. Energy Co~rr~e,~.Mgmr. 3X. (1). 319-332. In sizing air conditioning equipment, cooling load calculations are essential. The transfer function method (TFM), which is well known and adopted by ASHRAE, was programmed in this work to predict the hourly cooling load due to different types of wall, roof and fenestration. The developed computer code was found to be accurate when tested against hand calculations. In comparison with ASHRAE examples, some differences were noticed in the cases of cooling load due to wall and roof. In other cases, the agreement was perfect. The disagreement with ASHRAE results was pin-pointed, and the ASHRAE example was revised. The outputs of the program were also compared with the well-known Carrier program. showing satisfactory agreement. Various runs were made, and the results are discussed. The effect of changing the wall colour on cooling load and on so-air temperature was studied.
Eppelheimer, D. M. ASHRAE Trans., 1996. 102, Part?, SA-9&12-l, h73678. A method of controlling head pressure in water-cooled refrigeration systems has long been provided by varying condenser flow. Potentially greater energy savings, could be achieved by also varying the flow of water through the evaporators of chillers. The engineering problems that arise in the pursuit of this aim are discussed.
Harris, D. J. and Webb, R. S. Optimum venrilarion and airpow corlrrol in buildings.Proceedings 17th AJVC Conference Gothenhurg, Sweden, September 1996, 2, 613-621. Wind towers, as a method for cooling spaces. are reviewed in this work. Attempts to adapt this system, through scale models, as a way to avoid expensive air conditioning in office buildings, are presented.
97103231 Working fluids for mechanical refrigeration-invited paper presented at the 19th International Congress Refrigeration, The Hague, August 1995 Cavallini, A. Jnr. J. Refrig., November 1996, 19, (8) Proposed synthesised products to become immediate replacements for environmentally harmful fluids environmentally acceptable option of resorting investigated by examining some recent innovative refrigerants of some hydrocarbons, ammonia, carbon
485-496. drop-in or long-term are evaluated. The to natural fluids i\ applications such as dioxide, water and air.