So, in cooling conditions, it is common to require heat pumps that are designed only to provide heating. Now a
day, the cost of energy continues to rise and it becomes a imperative to save energy and improve overall energy
efficiency. A key idea for improving the energy efficiency of many industries is to recover every possible sources of
waste heat and convert this energy to a useful output [4]. Moreover, many efforts tried to increase the heat pump
performance. However, this study is aimed to investigate the hot water making potential by using the waste heat that
released from condenser of the air conditioner. The advantages of this system are as follows: 1) Save energy due to
use of the waste heat to produce hot water 2) Without electric short circuit and 3) Fast to produce hot water and 4)
Reduce green house gases [5]. So, some recent researches focused on this area are summarized as follows:
Roongutai et al. [6] studied the warm water making from air-conditioning system by using of the waste heat that
released from the air-conditioner. A pressure switch was used to activate both of the condensers, which are
automatically controlled. Their results indicated that the highest temperature of the water in the reservoir is 49 o
C
Saisanit et al. [7] design and construct the prototype of the hot water making machine using waste heat released
from a common air conditioner system. Two types of the hot water system such as “submerged coil” and “flow
through” are used in their study. Solenoid valves were used to control the flow direction of the refrigerant. Air
conditioner with cooling capacity of 3 TR and working with R22 was used in this study. The result indicated that the
hot water making machine with submerged coil type is more appropriate to use than the flow through type.
As mentioned before, the purposes of this study are to investigate the potential of hot water making by using a
conventional air conditioner as an air-water heat pump and then to compare the COP of the system between
conventional air conditioner cycle and heat pump cycle. The energy saving potential for making of 200 L hot water
is also presented.