Re: [EnergyPlus_Support] "Heat Absorption" in Water to Water HP

On Fri, Nov 11, 2011 at 1:29 PM, YuanLu Li <yli006@xxxxxxxxxxx> wrote:

Because it is over simplified.

COP is not a constant, if you need detailed performance value with different load.

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: kwalkerman@xxxxxxxxx
Date: Fri, 11 Nov 2011 13:22:38 -0500

Subject: Re: [EnergyPlus_Support] "Heat Absorption" in Water to Water HP

... I guess my only hesitation is that this is an easily calculated number - so why does it need inputting???

On Fri, Nov 11, 2011 at 1:13 PM, Karen Walkerman <kwalkerman@xxxxxxxxx> wrote:

Thanks Jim for your kind help. So, just to make sure I have this straight:

If I have a heat pump in heating mode with a total capacity of 660 MBH, and a COP of 3, the total heat "absorbed" (Heat of Absorption) would be 660 MBH - (660 MBH/3) = 440 MBH??

--
Karen

On Fri, Nov 11, 2011 at 12:43 PM, Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

p.s., Cooling capacity will be ~ Power input x EER

The Building Performance Team
James V. Dirkes II, P.E., BEMP , LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Karen Walkerman
Sent: Friday, November 11, 2011 12:00 PM

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] "Heat Absorption" in Water to Water HP

That is kind of what I thought it was - usually this is roughly equivalent to the grid energy (usually electricity) used to power the machine. If you have a 5KW machine, then either the system or surrounding space needs to absorb 5KW. If the load side absorbs the heat, this is considered part of the total heating capacity of the machine, right?

Unfortunately, this is not a number given by the manufacturer of the heat pump I'm currently modeling. What is a reasonable range for absorption versus reject to the space?

I assume that this absorption is absorption into the load water loop??

Thanks!

Karen

On Fri, Nov 11, 2011 at 11:50 AM, Pregas Srinivasan <pregas@xxxxxxxxx> wrote:

Water to water HP - Geothermal water loop removes the condenser heat rejected in summer. This heat is rejected to ground. In winter the water loop absorbs heat from ground and air stream gets heated in heat pump. How much of heat absorbed is given by HP unit selection and varies between unit manufacturers.

Let me know if this helps.

PS

On Fri, Nov 11, 2011 at 11:11 AM, Karen Walkerman <kwalkerman@xxxxxxxxx> wrote:

Hi,

In the document "WaterWater_PE_Heating.xls" (available on the helpdesk) can anyone shed a little light on what "heat absorption" (column G) means?

Thanks,

Karen