[Equest-users] Infrared Heaters

[Sami, Vikram]

My 2 cents.

Caveat: I have not actually modeled these (don’t really use them much in Atlanta).

I am assuming you have a separate HVAC unit in addition to these to supply ventilation air (or is it just the infrared heat?). The one’s that I have seen do not really have variable temperature controls  they are either on or off.

There are two components to this:

1.       Sensible heat gain to the space

2.       Radiant heat to occupants (radiant heat to surfaces will eventually end up as heat gain to the space – correct?)
Of the two – the first one is a comfort issue and the second is an energy issue. In eQUEST the only reason we care about the comfort issue is that it allows you to turn down the supply air.

My suggestion is that you can model it in two ways:


1.       Model it as an internal energy source (you can specify it as gas, electric or hot water). You can specify the input power as well as the Sensible Ratio. The drawback is that you cant control this by thermostat. But if the equipment is an on-off thing this doesn’t matter. The heat gain will be added to the space.

2.       This might be the more Accurate way to model this (although its more long winded). The first step is the same – you model it as an internal source. This is only to run the meter if it’s a gas or hot water  run radiator. If its electric you could probably skip this step. The next step is to add a lighting load equivalent to this. eQUEST allows you to separate lighting loads into radiative fractions and sensible fractions. The drawback of course is that you have an additional step to separate out the lighting loads from this (by running the model once without the additional loads in lighting).


Not sure if this will work, but hey – its free advice ☺

Vikram Sami, LEED AP
Sustainable Design Analyst
1382 Peachtree St. NE, Atlanta, GA 30309
t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com   www.perkinswill.com<http://www.perkinswill.com/>
Perkins+Will.  Ideas + buildings that honor the broader goals of society


From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of jeff at sharpenotes.com
Sent: Thursday, September 09, 2010 3:27 PM
To: Charles Land
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Infrared Heaters

Our approach has been similar, but with lower equivalent furnace efficiencies because of the typical flue losses and the bigger convective losses (heat off the top of the units).  Manufacturer claims of 85% efficiency seem typical for tube style units. Also note that most of the gas models do incorporate an exhaust fan for draw-thru.

From the DOE2 point of view, the energy savings are realized by the significantly lower space temperatures these systems allow.  In a cold environment repair garage application our most recent model predicts a 30-40% energy savings over conventional ceiling-hung unit heaters; matching the historical data we know of. j#

Sharpe Energy Solutions, Inc
Ashland, OR 97520

-------- Original Message --------
Subject: Re: [Equest-users] Infrared Heaters
From: Charles Land <cland at geo-marine.com<mailto:cland at geo-marine.com>>
Date: Thu, September 09, 2010 11:36 am
To: Peter Hillermann <peterh at westallarchitects.com<mailto:peterh at westallarchitects.com>>, "'BLafley'"
<BLafley at cetonline.org<mailto:BLafley at cetonline.org>>, "equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>"
<equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>>

Im not sure what your talking about as far as renewable energy, but ive always modeled infrared by dropping the zone temp setpoint by ten degrees, setting the fan energy to zero and making the furnace 100% efficient. Some times I lower the heating design temperature as well.

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org> [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Peter Hillermann
Sent: Thursday, September 09, 2010 12:42 PM
To: 'BLafley'; equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Infrared Heaters

Bill,

Do you have a chart that shows how much renewable energy the unit consumes
and then uses to create heat? What you need to do is create the item in 2
parts. Its renewable component, which might be a solar collector and then
you set up a radiant heater in the room either as baseboard or as your
system in that zone.The thing that I have noticed while modeling is there
are 2 things you are looking at.. products in your building and how they
consume energy, by amount and efficiency. The second is what are you doing
to replace the energy... renewable or are you pulling it from the grid. The
model does not care where it comes from as long as when you use the
renewable it is as efficient as you say it is. I typically use PVWatt
calculator and do manual calculations because someone taught me that. You
can also set up a collector in the utility&economics tab under photovoltaic
modules. This is where you will need the solar information on your
collector.

The weather file needs to be correct because this is where it is pulling
your solar radiation data from watts/meter squared or watts/feet squared.

Hope this helps. (Easier to do by hand)

Thanks,

PETER HILLERMANN

peterh at westallarchitects.com<mailto:peterh at westallarchitects.com>

westall
architects
3404 pierce drive
chamblee, georgia 30341

o 770.458.4113
f  770.458.5352
c 678.898.2936

westallarchitects.com<http://westallarchitects.com>




-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of BLafley
Sent: Thursday, September 09, 2010 10:22 AM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] Infrared Heaters

Hello,

Does anyone have any experience modeling ceiling hung infrared heaters in
eQuest?

Thanks,
--
Bill Lafley
Energy Analyst
Center for Ecological Technology (CET)
320 Riverside Drive - 1A Florence, MA 01062 blafley at cetonline.org<mailto:blafley at cetonline.org>
<mailto:blafley at cetonline.org> / 413-586-7350 ext. 222
413-695-2730 (cell) Visit www.cetonline.org<http://www.cetonline.org> <http://www.cetonline.org>
Support our work <https://www.merchantamerica.com/cet/echopay/index.php><https://www.merchantamerica.com/cet/echopay/index.php%3e>;

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