At present, the design of variable water air-cooled chiller system generally adopts the 1. secondary double-loop mode. The use of two water pumps to increase equipment investment; The mixing of water supply and return of air-cooled chillers affects the efficiency of the chiller at part load. When the actual high-load air conditioning demand conditions do not match the * * * design working conditions, the full load capacity of the chiller cannot be fully utilized and other adverse consequences. The above problems can be avoided by designing a single-loop air-conditioning air-cooled chiller system. The strengths and possible problems of the single-loop variable flow system are discussed, and a safe, stable and reliable control strategy for the chiller is provided over the entire operating range.

Conventional variable flow air-cooled chiller systems include primary and secondary loops with separate pumps. Usually, a loop with the refrigerator one-to-one corresponding low-pressure first pump to maintain a constant air-cooled chiller flow, and one or more high-pressure head variable flow secondary pump on the secondary loop cold water volume to adjust to meet the actual refrigeration needs. 1. the imbalance of the flow between the secondary loops causes the air-cooled chiller to flow in the bypass pipeline. Although this system achieves the goal of maintaining a constant air-cooled chiller capacity through the chiller, it cannot achieve high chiller efficiency at part load, and the capacity of the chiller is limited due to the unequal flow of the two loops under most operating conditions.

In order to realize the full potential of the variable flow air-cooled chiller of the integrated HVAC equipment operating under the high-performance control strategy, it is necessary to reconsider the actual configuration of the variable flow air-cooled chiller system. Recent studies have shown that we can use an integrated control strategy to directly adjust the pump speed without pressure control to meet the load demand, so that the variable flow air-cooled chiller distribution system to obtain higher efficiency. It is advisable to analyze the operation of the primary loop before adopting specific equipment configurations and control schemes.

In building refrigeration applications, the use of single-loop variable flow air-cooled chiller system although there are certain restrictions, but for the application of integrated high-performance DDC expertise designers, there are good reasons to consider the use of such a system. Carefully designed and integrated high-performance control operation of the single-loop variable flow air-cooled chiller system has the following advantages:

Simple equipment configuration saves initial investment, which can reduce system costs or invest in high-quality, long-life components.

The total energy consumption of the system is lower than that of non-integrated equipment configuration and control scheme.

The control precision is better than the traditional non-integrated control.

In order to take full advantage of the emerging HVAC integrated equipment with high-performance DDC systems, designers should consider the use of single-loop variable flow air-cooled chiller systems. In many typical applications, its benefits are obvious.