Possibilities of Adapting a Free-Cooling System in an Existing Commercial Building

Abstract

Increasingly, the exploitation of buildings involves the need for comprehensive management of all systems operating within it, their continuous monitoring, both for the safety of users and to mainly optimize the operating parameters of systems that are largely dependent on each other, interact with each other. This is mainly associated with the need for the most energy-efficient management of energy consumption, which has the largest share of operating costs. The main cost for the facilities is the cooling aspect, which is significant, and for this reason, it is necessary to analyze the possibility of its minimization. One of the possible systems to consider in order to reduce the consumption of cooling energy in the facility is the application of free-cooling technology, which is based on the use of the natural cooling capacity of the outside air for cooling rooms with high heat gains. The application of the free cooling system for facilities with a relatively stable cooling load, with significant heat gains from equipment is justified due to the possibility of maintaining low room temperatures, below the comfort value for people, for a long period of time. The problem arises when a large proportion of the heat gains are from people. In such a situation, cooling of rooms is possible but requires a large amount of ventilation air, which is already a serious limitation on the one hand because of the existing air conditioning equipment, lack of possibility to increase the ventilation air stream; on the other hand, the low heat capacity of the air itself, compared to, e.g., water systems used for cooling of the facility or multisplit systems. These limitations put a question mark over the possibility of adapting the technology of free cooling for the existing facilities, where the majority of heat gains come from people. It is not possible in such objects to lower the room temperature below the limit values for the sake of thermal comfort, which in itself limits the possibilities of using air as a natural cooling agent in such objects. Based on the measurement data obtained from the object, it was decided to check the possibilities of applying free-cooling technology in a large shopping facility and obtaining an answer as to what extent it is possible to reduce the power of cooling units with the application of free-cooling exchangers.