[TRNSYS-users] questions about ground source heat pump system using type668

[Jiang Shuang]

Some questions that have puzzled me for days that I have to write to you for help. I'm trying to modeling a ground source heat pump system which supplies chilled water in summer and hot water in winter to a common office building. In transition seasons, the system doesn't work. Unlike the model given in trnsys, I choose water-to-water heat pump (type668) for use. The project I made is attached following. The problems are as follows:

(1)I use type515 and type14 combined with an equation to control the water-to-water heat pump. When the heating signal is 1, it works under heating mode, and when the cooling signal is 1, it works under cooling mode. However, I find that when both heating signal and cooling signal change to 0, the heat pump stop working, but it still has a power output! I have used the control part to a water-source heat pump (that's type505 in trnsys), and all components work well. 

(2)I find the example about type668 given in trnsys is about hot water producing and more examples in the internet are also about heating. But in my country, it is common that ground source heat pump is used to produce chilled water and hot water to air conditioners in a building, in which they exchange heat with the outdoor air. Then the airs are distributed to rooms. My question is that if type668 can be used for the above purpose. If not, which type should I choose? 

(3) The vertical u-tubes (type557) has a parameter: number of boreholes in series, what does it mean? If there are many series parallel loops (It is common in practice), what should I do?

So much questions, but I'm really incapable about these questions. Thanks for your reply.



		
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