[EnergyPlus_Support] Re: Variable Volume Refrigerant System

[Mário <mneves32@xxxxxxxxx>]

Hello James 

Thank you for your Input.

Based on tour idea,  I think that the curve operation for the equipment is a good idea, but what if the chiller and heat pump has similar operation curves to those of the production equipment of the VRV?
I don´t know how the energy building certification work´s in your country but in Portugal we use an asset rating in order to classify the building. For example in the case of a office building the occupant loads are much smaller then from the actual operation load (outside air include). This means that if the HVAC in the builing is a VRF system you constantly will be be working with the machines at very low load which means that the VRF is not beaming used at it´s optimal working point.All this text has the conclusion that a water system has the flexibility for load adaptation, which compared to the 14% minimum load operation of the VRF system is good. (Just a though)

I´am going to think about your idea.
Thank you once again.
Mário Neves 


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "James V Dirkes II, PE" <jvd2pe@...> wrote:
>
> Dear Mário,
> 
>  
> 
> I'm currently working on a VRF system and am modeling it this way:
> 
>  
> 
> ·         The actual system uses Mitsubishi City Multi VRF units with heat
> recovery capability.  I am not sure if this approach will work for other
> manufacturers of VRF systems.
> 
> ·         My model uses water source heat pumps (WSHP) for each zone. These
> should capture the ability of the VRF system to "shift" energy around when
> some zones are heating while others are cooling.  The model is running
> without error, but I have not addressed the details of the energy portion
> yet.  That part will go similar to the following?
> 
> o   The WSHP fans will be assigned power (efficiency and pressure rise) to
> match the VRF fans.
> 
> o   The WSHP heating and cooling coils will have a "simple" power
> consumption coefficient.  If I can use 0 power, that will be best, since the
> VRFs don't use power at each zone except for the fans.  If I can't use 0 due
> to some E+ restriction, I'll probably make it equivalent to a COP as high as
> possible and then report that energy in a Custom Meter and use a Custom
> Decrement Meter  so it can be removed from the total electricity use.
> 
> o   The WSHPs have a gas boiler with efficiency of 1.0 for supplemental heat
> and an electric chiller with COP of 1.0 for supplemental cooling.  The 1.0
> efficiency / COP values are used for simplicity so that energy used by the
> boiler and chiller is essentially the same as the load.
> 
> o   I will report the boiler and chiller energy and "post-process" their
> energy using the manufacturer's part load efficiency equation.  It occurs to
> me just now that I may be able to apply curve values which mimic the
> manufacture part load performance and avoid the post processing?.
> 
>  
> 
> The Building Performance Team
> James V. Dirkes II, P.E., LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
> 
>  
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Mário
> Sent: Sunday, May 16, 2010 4:12 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Variable Volume Refrigerant System
> 
>  
> 
>   
> 
> Hello 
> Does anyone have any ideas on how to model a variable volume refrigerant
> system, like a VRV or VRF system in which you have one exterior machine
> linked to vários interior terminal machines?
> Thank´s
> MN
>




------------------------------------

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/