[Equest-users] Modelling losses in chillers

Sharad Kumar sharadcapricious at gmail.com
Fri Aug 10 06:56:52 PDT 2018


Hi Vishal,




As per my understanding you will have to account with the Loop Design Delta
T losses for getting the result.

The Case that I am taking is having a Loop Design Delta-T of 10 degree
Fahrenheit which is as follows as an example of Loop Design Delta-T.







So the changes that you are required to have is the 5% losses in the loop
Delta-T design which has to be taken as 0.5 degree Fahrenheit in the Supply
Loss DT. The change that you are required to do is in the cooling
circulation loop in the losses tab which is as follows:






For Heating the Design Delta-T in my case is 40 degree Fahrenheit which is
given as below:




The assumed changes required to be done is to change the Looses Delta-T for
heating in the heating circulation loop. The required loss is 10%, hence
the loop Design Delta-T losses is 4 degree Fahrenheit has to be taken:






With the help of these two changes in the Cooling and Heating Circulation
loop in the losses tab one can achieve the percentage losses as required by
the reviewer.





*Thanks,*

Sharad.Kumar.

+91-9102906597

Freelancer (Energy Simulation)

India.


.........................................................................................................................................

---------- Forwarded message ----------
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To: equest-users at lists.onebuilding.org
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Date: Thu, 9 Aug 2018 15:26:17 +0530
Subject: [Equest-users] Modelling losses in chillers

Hola Modelers,



Its time that I need some help!!


My building includes chilled water district cooling system in which I have
received a review comment which is as follows:



*“If following Option 2 of the district thermal guidelines the Proposed
model must reflect a virtual plant with the same average efficiencies of
the entire upstream district energy system based on actual loading (average
efficiencies can be determined using either the Monitoring or Modeling
methods described in Appendix C). Alternatively, the default plant
efficiency values outlined in Section 2.4.1.2.3 of the guidelines (4.4 COP
for DES cooling plant and 70% for DES heating plant) may be may be used to
reflect the district energy plants in the Proposed model**. In addition,
thermal distribution losses must be accounted for in the Proposed model
based on the losses determined in the actual design or the default values
outlined in Section 2.4.1.2.3 of the guidelines may be used (5% for chilled
water district cooling, 10% for hot water district heating, 15% for closed
steam loop, or 25% for open steam loop)**”*



Can anyone help me on how should I account 5 % losses mentioned in the
comment (highlighted in red)??



Waiting for the reply.



Thanks

Vishal
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