/ep_edm/en/contect_989.html SHINI PLASTICS TECHNOLOGIES, INC.

Special Reports

2015 Quarter 4 Issue 25

Temperature Control for Water Chiller Outlet Water

Share to:

The temperature control for the water chiller; outlet water can be illustrated from two aspects. First, is the temperature control accuracy requirement of outlet water. Then, is the way to realize temperature control accuracy for outlet water.

As a standard temperature control requirement, it requires2temperature difference of water chillers produced by Shini Group currently. This means when the machine outlet water temperature is2higher than a set value, it reaches the shutdown time, which makes the machine re-start for cooling. Society is putting forward higher requests for these products and enterprises aim to improve production efficiency to lower costs. More strict and diverse temperature control accuracy is in turn demanded. Since there are consistent improvement needed for water temperature in the industry, Shini Group also has to follow market requests to produce the water chillers, improve the technology, and updating design while promoting a machine’s performance consistently. 

As to meet the above requirements for temperature difference control, it must adopt essential measures to realize this control. First, the function of hot-gas by-pass is usually the applied method to make the temperature control accuracy within ±1℃for industrial water chillers. The hot-gas by-pass valve can adjust the refrigerant flow that enters the evaporator, which reduces said evaporator’s heat exchange energy. By utilizing the work of the by-pass valve to control output energy matching the generated heat from the client’s side, it lowers the fluctuation range of temperature. The advantage of this method lies in low costs and simple structure. Based on previous designs, it only added the by-pass valve, which caused a shortage in the excessive work of the by-pass valve. This led to a large impact to the water chillers’ refrigeration system, resulting in unit damage and shortening the service life. Secondly, to employ inverter water chillers, the inverter compressor could according to feedback from outlet water temperature, adjust the rotating speed of the compressor. This changes the output energy of water chillers and matches the required energy of the client’s side. The advantage of the inverter unit lies in more accurate temperature control, stabilization and the reliable operation of such compressors. As the usage time increases, compared with constant-frequency unit’ operating costs, it would manifest much more advantages in costs. As there are large differences with the constant-frequency unit, the whole machine needs re-designing, costing about 50% more than the constant-frequency unit. The result is acquiring large input in early investments. Moreover, to enlarge the water tank capacity for ensuring it could satisfy the temperature rising request of outlet water when unit shutdown, it had to reach the temperature control requirement in turn. The solution is also relatively easy to achieve, but the question is that it needs the accordance with the customer’s temperature control demand. To ensure an efficient capacity of the water tank, the water tank should be mounted outside. That reduced the floor space of the unit, because every different water tank added production costs and prolonged the delivery, so this solution usually applied for the central chilling water system. 

 By comparison of these three solutions, we find that each one has its targeted area. In actual application, it is up to the customer’s benefit to select the most suitable solution.