2018 Volume 43 Issue 254 Pages 33-42
The aim of this study is to develop an optimal operation technology for an HVAC system. To this end, an HVAC system is appropriately operated on the basis of the outside air and loading conditions to eliminate wasteful operation. Moreover, an optimal operating method is examined for a heat source system, including variable air volume control of a cooling tower fan. The optimal set points for the cooling-water temperature and cooling-tower-fan frequency were analyzed using an energy simulation tool. A relational formula for optimal operation of the heat source system was derived by analyzing the result. The approximated relational formula was used to determine the optimal set point of the cooling-tower-fan frequency from the outdoor wet-bulb temperature and the load factor of the chiller. A method in which the cooling-tower-fan frequency was considered the set value was compared with another method in which the cooling-water temperature was considered the set value. The results show that the former method was superior when the input of the outside air wet bulb temperature and the load factor of the heat source machine differ from the original value, and the former method was more accurate approximation. Further, the energy consumption of a heat source system was determined using various control methods. The calculation results show that the energy consumption could be reduced using the optimal operating method with the help of the relational formula. In addition to the simulation, the energy-saving effects of the method were confirmed from a field test.
