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Energy Saving Tips 

Often times, people search for energy saving tips to improve the efficiency of their refrigeration plants. Is it a good idea to get as many energy saving tips as possible?

Energy saving tips will give us direction for potential energy savings. This is the first step in the energy saving process. Determination of the optimum set points is the second step. Implementation of the optimum set points is the third step in the energy saving process.

Example.

Optimum condensing pressure is a major energy saving measure. Very often, this measure will give us up to 50% of total energy savings. During winter operation, optimum condensing pressure can be as low 60 psig. This means that the lower the condensing pressure, the better the plant efficiency. This is well known. However, implementation of the mentioned energy saving measure is different. Many refrigeration plants operate at unnecessarily high condensing pressure. It is easy to run the plant at 120 psig condensing pressure or higher and everyone can do this. It is not easy to run the plant at a condensing pressure below 100 psig. There are several barriers to low condensing pressure. These barriers are hot gas defrosting, liquid supply, liquid injection oil cooling, oil carry over and etc. However, every barrier has a solution. Very often a barrier has several solutions and you can choose the solution that is better suitable for your refrigeration plant.

Many people believe that hot gas defrosting at low condensing pressure will take much longer than hot gas defrosting at high condensing pressure. The majority of low temperature evaporators are bottom feed overfed coils. I found that during defrosting at high condensing pressure, many evaporators are oversupplied with hot gas. This oversupply creates a lot of ammonia condensate. It is not easy to remove this condensate from the coils, because it should be pushed trough small orifices that are located at the entrance of each circuit. This excessive condensate will slow down the defrosting at high condensing pressure. To get adequate defrosting at low condensing pressure, hot gas supply and condensate draining should be balanced. Operation of the refrigeration plant at condensing pressure below 100 psig will save you a lot of energy.

You can find several dozen energy saving tips, but only a few of these tips can give us good energy savings. The majority of these tips are almost useless. To get maximum energy savings, you should be focused on determination and implementation of the optimum set points for major energy saving measures.

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