[Equest-users] PTAC and PTHP
Eddie Corwin
ecorwin at altanova-energy.com
Thu Nov 4 12:58:46 PDT 2010
Oops, I meant to say -13*F in my previous post (in reference to the Mitsubishi
Citi Multi-Split operating temperature)
________________________________
From: "Gary.Schrader at buildings.schneider-electric.com"
<Gary.Schrader at buildings.schneider-electric.com>
To: equest-users at lists.onebuilding.org
Sent: Thu, November 4, 2010 3:44:38 PM
Subject: Re: [Equest-users] PTAC and PTHP
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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