THERMAL SCIENCE
International Scientific Journal
EFFECT OF ROUGHNESS GEOMETRY ON HEAT TRANSFER AND FRICTION CHARACTERISTICS OF PCM STORAGE UNIT FOR NIGHT COOLNESS STORAGE IN SUMMER SEASON
ABSTRACT
This paper presents a theoretical analysis of thermal storage unit using phase change material (PCM) as storage medium. Storage unit consists of parallel rectangular channels for the air flow which are separated by phase change storage material. The purpose of storage unit is to absorb the night coolness and to provide cooled air at comfort temperature during day time in summer season. MATLsimulation tool has been used to compute the air temperature variation with location as well as time, charging and discharging time of storage unit. Phase change material used for analysis is selected in such a way that it’s Melting point lies between comfort temperature and minimum night ambient temperatures. The air flow rate needed for charging of PCM is approximately four times greater than the flow rate required during day time to achieve comfort temperature for approximately eight hours, due to limited summer night time (only eight hours). The length of storage unit for which NTU value is greater than or equal to five will give the exit air temperature equal to PCM temperature for the case of latent heat utilization. It is found that artificial roughness on the duct surface effectively reduces the length of storage unit in the cost of some extra pressure drop across the duct.
KEYWORDS
PAPER SUBMITTED: 2011-05-11
PAPER REVISED: 2012-02-10
PAPER ACCEPTED: 2012-02-10
THERMAL SCIENCE YEAR
2013, VOLUME
17, ISSUE
Issue 2, PAGES [365 - 375]
- Hed, G. & Bellander, R., Mathematical modelling of PCM air heat exchanger. Energy and Buildings,
8 (2006), pp. 82-89
- Alkilani, M. M., Sopian, K., Sohif, M., Alghoul, M. A., Output Air Temperature Prediction in a Solar
ir Heater Integrated with Phase Change Material, European Journal of Scientific Research, 27 (2009),
, pp. 334-341
- U. Stritih, V. Butala, "Energy saving in building with PCM cold storage" International
ournal of Energy Research, vol. 31, 2007, pp. 1532-1544.
- Arkar, C. & Medved, S., Free cooling of a building using PCM heat storage integrated into the
entilation system, Solar Energy, 81 (2007), 9, pp. 1078-1087
- Medved, S. & Arkar, C., Correlation between the local climate and the free-cooling potential of latent
eat storage, Energy and Buildings, 40 (2008), 4, pp. 429-437
- Morrison, D. J. and Abdel-Khalik, S. I., Effects of phase-change energy storage on the
erformance of air-based and liquid-based solar heating systems, Solar Energy, 20(1978), pp. 57-67
- Solomon, A., Some of approximations of use in predicting the behavior of a PCM cylinder array.
etters in Heat and Mass Transfer, 8 (1981), pp. 237-246
- Virgone, J., Kuznik,F., Johannes, K., In-situ study of thermal comfort enhancement in a renovated
uilding equipped with phase change material wallboard Renewable Energy,36 (2011) , pp. 1458-1462
- Susman, G., et. al., Tests of prototype PCM ‘sails' for office cooling, Applied Thermal Engineering, 31
2011), pp. 717-726
- Incropera, F. P., Dewitt, D. P., Fundamentals of Heat and Mass Transfer, Jhon Willy &Sons,
NDIA, 2008.
- Sharma, M., Varun, Performance estimation of artificially roughened solar air heater duct
rovided with continuous ribs, International Journal of Energy and Environment, 5 (2010), 1, pp. 897-910
- Nicol, F. & Roaf, S., Pioneering new indoor temperature standards: the Pakistan project,
nergy and Buildings, 23(1996), pp. 169-174
- Raja, I. A., Nicol, J. F., Mccartney, K. J. & Humphreys, M. A., Thermal comfort: use of
ontrols in naturally ventilated buildings, Energy and Buildings, 33(2001), 235-244
- Verma, S. K., Prasad, B. N., Investigation for the optimal thermohydraulic performance of
rtificially roughened solar air heaters, Renewable Energy, 20 (2000), pp.19-36
- Saini, R. P., Saini, J. S., Heat transfer and friction factor correlations for artificially roughened
ucts with expanded metal mesh as roughened element, International Journal of Heat and Mass
ransfer, 40 (1997), pp. 973-986.
- Momin, M. E., Saini, J. S., Solanki, S. C., Heat transfer and friction in solar air heater duct
ith V-shaped rib roughness on absorber plate, International Journal of Heat and Mass Transfer, 45
2002), pp. 3383-3396
- Bhagoria, J. L., Saini, J. S., Solanki, S. C., Heat transfer coefficient and friction factor
orrelations for rectangular solar air heater duct having transverse wedge shaped rib roughness on the
bsorber plate, Renewable Energy, 25 (2002), pp. 341-369
- Layek, A., Saini, J. S., Solanki, S. C., Second law optimization of a solar air heater having
hamfered rib-groove roughness on absorber plate, Renewable Energy, 32 (2007), pp. 1967-1980
- S.K.Shukla, and S.K.Singh, Analysis of PCM Storage Unit for night coolness storage in
ummer season, International Journal of Sustainable Energy, 30 (2011) pp.1-13.