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cedkessler
Posts: 17
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 Posted: Wed Jun 25, 2008 9:37 am Post subject: HVAC and DHW |
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Hi, i've got few questions about the different parameters and settings for Hvac and DHW.
1) When using a split/multi-split system as HVAC system, onto the heating tab, Design builder ask for the SEER (SEER for a heat pump). Following all the researches i did, i've only found definition of SEER/EER for cooling. Even in the "Non domestic HVAC Guide" nothing is mentioned about SEER for heat pump. The only efficiency about heating is referred as COP, coefficient of performance which does not include calculation on seasonal efficiency. My question is, should i enter the simple COP or could you give me any details on how to calculate the SEER for a heat pump?
2) About DHW parameters. When defining a DHW system, onto the tab "general" when asked for storage and second circulation details, the value by default is "auto". My question is, if using "auto" how are these values calculated by Design builder (or SBEM maybe)? Does it calculate it in function of the volume of the room or/and occupancy/activities, etc...
Thank you for your help,
Regards,
Cedric |
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cedkessler
Posts: 17
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| Posted: Thu Jun 26, 2008 9:17 am Post subject: |
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| Could anybody help me please? |
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less
Posts: 21
Location: Birmingham, UK |
| Posted: Sat Sep 13, 2008 10:25 am Post subject: |
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Hi Cedric
There are different terms used to represent the efficiency in the Non-Dom Guide and this is probably why the term SEER appears. They are all 'meant' to represent the seasonal efficiency based on energy out/energy in as a decimal fraction. I would simply use 'The Guide' to define how the efficiency is to be calculated and not worry too much about the term used or how representative it is.
Regards
Andrew Bairstow
SBEM Forum Assistant |
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adrien26
Posts: 20
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| Posted: Tue Sep 16, 2008 11:02 am Post subject: |
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| less wrote: | Hi Cedric
There are different terms used to represent the efficiency in the Non-Dom Guide and this is probably why the term SEER appears. They are all 'meant' to represent the seasonal efficiency based on energy out/energy in as a decimal fraction. I would simply use 'The Guide' to define how the efficiency is to be calculated and not worry too much about the term used or how representative it is.
Regards
Andrew Bairstow
SBEM Forum Assistant |
Hi Andrew,
I understand that we can use the ratio input/output for chiller systems.
However for heating boilers, no guidance is given when the SEER is not possible to calculate. From our experience, about 80% of the time, boiler part load gross efficiency is not available and therefore we have to input the default value being 65% or 81% depending on the age of the boiler.
We usually have access to boilers test report giving indication on the gross efficiency which is usually closer from the seasonal efficiency than the default value (especially when the default is 60%).
If gross efficiency could be used it would get some our building jump from one band to the other as heating can be the most important parameter for office type of building.
Could you please let me know if gross efficiencies can be used when SEER not available?
Best regards,
Adrien Strzyzewski
Green Energy Partners Ltd |
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less
Posts: 21
Location: Birmingham, UK |
| Posted: Fri Sep 19, 2008 10:43 am Post subject: |
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Hi
I am not a mechanical engineer so can't quote with that expertise but if it can be safely assumed that boiler part load efficiency is greater than full load efficiency then you know that the seasonal efficiency must not be less than the full load value. Thus it would be perfectly reasonable to take this value.
Andrew Bairstow
DesignBuilder Support |
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