High-efficiency chiller system             One of the main factors that boosts the use of energy consumption is climate situation. Thailand is known as a country based on a tropical location, resulting in the fact that almost industrial factories need air-conditioning system to decrease the heat issue. It is not only to setting the appropriate coldness, but also for to controlling the quality of production while energy budget wasting for subsiding the problem has to be taken into account at the same time. For most of industrial factories, more than half of the electricity costs is wasted in the air-conditioning system, meaning the increasing of production cost. To present to solution of solving this important problem, high-efficiency chiller system is introduced to reduce the energy cost and budget cost for the factories in all industry fields.           Chiller -- is a large cooling equipment functioning in water-cooling production or producing the cold-temperature water and send to the available air-conditioners located in several rooms of each building in the organization.          Chiller principle is to bring the refrigerant (cold gas under pressure) that is in the saturated state to be compressed at the compressor until the refrigerant transform  to be the heat substance (superheated vapor), with high pressure and high temperature. Afterwards, the refrigerant will move through the condenser for transferring heat out of the refrigerant and change to the fluid state with high pressure. Then, saturated liquid with high pressure will move through the expansion device (voltage reduction device). Refrigerant will have 2 states which are liquid and gas at low temperature and low pressure. Later, it will pass into the evaporator, making the refrigerant receives the heat from each load and become saturated steam. The cooling cycle will continue like this repeatedly, always circulating. Thus, chiller then is able to produce cold water continuously. This cold water can be sent to the air conditioner in each building, even located far from the chiller. The chiller is one part of all air- conditioning system that consumes the energy up to 52%.            Today, new-generation chiller will be designed and developed to have the kW per ton of cooling operation lower than the old-generation chiller. Consequently, it can save energy more than the old version about 20-30%. Moreover, new-generation chiller, mostly, will use the cooling substances without CFC that will create no harm to the earth's atmosphere as well.