Yamasaki measured the heat trans- missions of such walls and reported the relationship between indoor–outdoor air temperature differences and indoor air conditioner energy consumption during the winter. The three types of walls were com- posite wood and mud walls (Type WM), traditional mud walls (Type M), and insulated walls that are currently used widely (Type I). Three experimental buildings were constructed in the same region with identical parameters except for wall specifications, and simultaneous measurements were conducted for indoor and outdoor air temperatures and electric consumption by air conditioning (electric consumption).
Moreover, through an experimental model equipped with wooden board inside mud walls, the effect of wood on improvement in the thermal performance of house with mud wall is investigated. This study reveals the influence of wooden-housing-wall structures on indoor thermal environments and assesses the energy reduction performance of housing made with natural building materials. by designing an air conditioning system with Calcium Chloride CaCl 2 as phase change materials (PCM) and air Show more
#Coolpack refrigeration utah free#
The concept of free cooling was developed by Momeni et al. 1) in building walls, 2) in other building components, other than walls such as floor and roof 3) phase change materials in heat and cold storage units. In buildings, phase change materials are used in three different ways for cooling and heating. As a representative from middle east countries, in association with Daikin, Kuwait is in the process of evaluating the refrigerant Difluoromethane under high ambient temperature. Study and analysis of hydrocarbon type of refrigerants showed less power consumption and less compressor work in comparison with tetrafluoroethane (R-134 (a)). In fact, the direction of the ongoing research is shifted to the safer refrigerants along with good environmental properties. Mixture of hydrocarbons, propane (R-290) and isobutane (R-600a) were among the main refrigerants, but due to the disadvantages like, flammability and safety purposes and the use is limited. The experimental results showed that the coefficient of performance (COP) of the system with R- 422d showed 20% less compared to R-22 System and this is because of the high vapor density and low cooling capacity. R-22 was replaced by R-422 d by Aprea et al. The experimental results showed that, the mass flow rate of the refrigerants needs to be improved. R-22, the popular refrigerant used in air conditioners, was replaced by HFC- 422a and HFC-417b by Llopis et al. Among hydrocarbon pure fluids, propane and isobutene are finding much attention as a substitute to CFC-12 in recent years. The hydrocarbons do not destroy the ozone layer and their global warming potentials are hundred times lower than that of CFCs and ten times lower than other CFC substitutes.
The main motivation to adopt hydrocarbons in spite of their high inflammability is being eco-friendly. It extracts heat from a cold space and rejects heat to a high temperature heat sink. The system requires input in the form of mechanical work. It should be observed that the system operates on a closed cycle. This low pressure and low temperature refrigerant vapour evaporates in the evaporator taking heat from the cold region. In the expansion valve the pressure and temperature of the refrigerant decrease. To complete the cycle, the high pressure liquid is made to flow through an expansion valve. Hence when the high pressure, high temperature refrigerant flows through the condenser, condensation of the vapour into liquid takes place by heat rejection to the heat sink. The refrigerant vapour from the evaporator is compressed in the compressor to a high pressure at which its saturation temperature is greater than the ambient or any other heat sink. The refrigeration effect is obtained in the cold region as heat is extracted by the vaporization of refrigerant in the evaporator. As shown in the figure the basic system consists of an evaporator, compressor, condenser and an expansion valve.