Professional Advice

I heard from one manager that design and operation of their refrigeration plant was reviewed by a professional engineer. This engineer suggested several energy saving measures, but all these measures were very expensive.

Typically, a professional engineer designs a refrigeration plant for maximum refrigeration load and for the hottest ambient conditions. However, majority of energy savings can be achieved during periods of cool weather through optimized operation of the refrigeration plant. Unfortunately, professional engineers were not taught to optimize operation of the refrigeration plants. To be an expert in optimization, engineer should do his own study in this area of energy savings. However, this is a very time consuming process. Majority of engineers simply do not have time for this study. This is the reason that they can not give you good professional advice about optimized operation of the refrigeration plant. It means that it is not easy to find energy efficiency adviser, who can give you correct information about cost effective energy savings. If you did not get good advice, it can lead to significant investments without significant energy savings.

Example.

One company installed air curtains for freezer doors to minimize infiltration of warm air into the freezer. To save energy, these air curtains were heated by ammonia hot gas. Surprisingly, heating coils of the curtains were designed for condensing pressure of 150 psig. It means that a refrigeration plant should be operated at 150 psig of the condensing pressure all year around. During periods of cool weather, majority of the refrigeration plants can be operated at condensing pressure below 100 psig. Operation at 150 psig of condensing pressure will waste a lot of energy. It looks like people use 2 KWh to save 1 KWh. Most likely, the designers of these heating coils and/or these freezer doors have limited knowledge about optimization of the refrigeration plant operation, because heating coils can be designed for the condensing pressure 100 psig or lower by increasing heat transfer surface of these coils and a lot of energy can be saved.

I think that managers of every company should choose energy efficiency adviser wisely. A good adviser will be able to help you to maximize energy efficiency of your refrigeration plant with minimal investments.