[Equest-users] PTAC and PTHP

[Gary.Schrader at buildings.schneider-electric.com]

In addition to Eddie's comments, I would advise referring to
manufacturer's documentation for heat pump performance. Performance
varies by brand, model, capacity, and ambient conditions. I have
experience with several heat pumps operating well into the teens. Others
claim they can perform well below zero. Capacity charts and performance
curves will tell you what the capacity is at various conditions. For the
purposes of your model, I would ensure that you are using performance
curves reflective of the equipment you intend to install in your room.

 

-Gary


________________________________________________________________________
_______________________________________________

Gary Schrader | Schneider Electric | Buildings Business | Energy
Solutions | Engineer I
Phone: +1 913 217 8068 | Fax: +1 913 469 0206
Email: gary.schrader at buildings.schneider-electric.com | Site:
www.schneider-electric.com/buildings | Address: 16011 College Boulevard,
Suite 212, Lenexa, KS 66219, USA

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From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Eddie
Corwin
Sent: Thursday, November 04, 2010 2:17 PM
To: deepika khowal; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] PTAC and PTHP

 

A heat pump are a MUCH more efficiency way of heating.   The only issue
with heat pumps are that they do not work well in cold weather (<40*F)
below this temperature, they are pretty much electric resistance
heaters.  A lot of improvements have been made, for example, the
Mitsubishi Citi Multi-Split systems can operate at temperatures as low
as 13*F.  For these types of systems, they operate as Heat pumps at 40*F
and above.  At 40*F and below, they use electric resistance heat to warm
the air flowing over the outdoor unit (allowing for heat transfer
between the air and the refrigerant).  So once you get down to 13*F they
start to use a lot of electric resistance heating.  Still much better
that pure electric resistance heating!

 

-Eddie

 

________________________________

From: deepika khowal <deepika.khowal at gmail.com>
To: equest-users at lists.onebuilding.org
Sent: Thu, November 4, 2010 2:52:38 PM
Subject: [Equest-users] PTAC and PTHP

HI 

I am trying to model a room with 80% glazing which has a wall unit air
conditioner.

what will be the difference PTAC using electric heat / heat pump for
heating ?

which one is advisable in terms of efficiency and energy savings?

does anyone has any thought on this?

Thanks

Regards

Deepika


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