http://www.coldsystemsllc.com/blog/2010/01/unintended-consequences/ Fri, 10 Sep 2010 20:32:08 +0000 http://wordpress.org/?v=2.7.1 hourly 1 http://www.coldsystemsllc.com/blog/2010/01/unintended-consequences/comment-page-1/#comment-17 admin Tue, 12 Jan 2010 14:13:17 +0000 http://www.coldsystemsllc.com/blog/?p=214#comment-17 Thanks for the reply Jon. The points you raise are good as they direct parties to look for other options. That is one of the reasons why this was posted. It is my feeling a lot of systems are designed in a similar manner, which perpetuates the inherent limitations. By looking at those barriers and understanding the underlying fundamentals we can bridge the gap between <em>the way it's always done</em> to something that works well in all conditions. Sorry for the confusion on the posting. The spam blocker holds comments for approval. Thanks for the reply Jon. The points you raise are good as they direct parties to look for other options. That is one of the reasons why this was posted. It is my feeling a lot of systems are designed in a similar manner, which perpetuates the inherent limitations. By looking at those barriers and understanding the underlying fundamentals we can bridge the gap between the way it’s always done to something that works well in all conditions. Sorry for the confusion on the posting. The spam blocker holds comments for approval.

]]> http://www.coldsystemsllc.com/blog/2010/01/unintended-consequences/comment-page-1/#comment-15 Jon Edmonds Tue, 12 Jan 2010 13:51:55 +0000 http://www.coldsystemsllc.com/blog/?p=214#comment-15 A good analysis of "false" economies. However, there is a solution for the ammonia head pressure deal and still enjoy the lower BHP/TR and increased capacity with lower head pressure.. As you note, a pressure regulating valve can be located in the compressor discharge line to provide enough pressure and temperature to regulate defrost. If the designer is smart he will place the regulating valve in only one of the compressors assuming the system has more than one compressor and will energize this valve to raise the pressure only when defrost is required. Of course,it goes without saying that the branch take off for the defrost gas is placed between the compressor discharge and the regulating valve. Another economic design is to pipe the return defrost condensate and attendant gas to an intermediate temperature level such as a flash economizer assuming there is one present rather than to the colder low pressure receiver. A good analysis of “false” economies. However, there is a solution for the ammonia head pressure deal and still enjoy the lower BHP/TR and increased capacity with lower head pressure.. As you note, a pressure regulating valve can be located in the compressor discharge line to provide enough pressure and temperature to regulate defrost. If the designer is smart he will place the regulating valve in only one of the compressors assuming the system has more than one compressor and will energize this valve to raise the pressure only when defrost is required. Of course,it goes without saying that the branch take off for the defrost gas is placed between the compressor discharge and the regulating valve. Another economic design is to pipe the return defrost condensate and attendant gas to an intermediate temperature level such as a flash economizer assuming there is one present rather than to the colder low pressure receiver.

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