[bldg-sim] Radiant Heating/Cooling

Peter Simmonds peter.simmonds at ibece.net
Wed Apr 14 07:46:57 PDT 2004


I do not fully agree with this statement. I have been using radiant systems in buildings for more than 20 years and with the correct application the energy comsumption compared to a traditional system, say overhead VAV can vary from 15% to 30% savings. At present, here in California project such as The Water and Life Museum, Los Angeles Valley College, Westminster Cultural Center and the Childrens Museum of Los Angeles are all showing substantial savings when integrating radiant systems into the designs (compared to an overhead VAV system. Most of these designs are primarily cooling dominated and that probably makes this statement very suprising and of course I am bias. I have published several ASHRAE papers on the potential savings and increased comfort of radiant systems. Another little project I forgot to mention was the Bangkok airport project which will have about 270,000 m2 of radinat cooled floor and the predicted energy savings were in the order of 40%.
I dont think this forum is a place to say mine is bigger than yours, but Rick Strand and David Sheatzle have been very progressive in trying to get a radiant model in energyplus. A model that works and one that can be applied by enginerrs designing real buildings.


Peter Simmonds, Ph.D.
IBE Consulting Engineers
5910 Lemona Ave. 3rd Floor
Van Nuys, CA 91411

tel: 818-947-0000 #246
fax:818-947-0047
cell: 818-219-1284


-----Original Message-----
From: Edward F. Sowell [mailto:sowell at fullerton.edu]
Sent: Tuesday, April 13, 2004 6:43 PM
To: bldg-sim at gard.com
Subject: [bldg-sim] Radiant Heating/Cooling


This is a claim made primarily by the industry making radiant
equipment. I have never seen convincing evidence. It has always
seemed to me to be a second-order effect at best.

Ed Sowell

>
>
> In your research with radiant heating cooling savings, have you found any
> energy "savings" that can be attributed directly to the use of
> the radiant
> system vs other systems (air supply in particular).  For example, I have
> seen some papers that note that the heating setpoint can be relaxed while
> still maintaining thermal comfort with a radiant system.
>
>
> At 10:47 07/04/2004, you wrote:
> >Dear All,
> >
> >For those interested in the simulation of radiant
> heating/cooling systems,
> >IRC has developed a semi-analytical model for integration in energy
> >simulation software that use the one-dimensional numerical modeling to
> >calculate the heat transfer within the building construction assemblies.
> >
> >The model combines the one-dimensional model of the energy simulation
> >software with a two-dimensional analytical model.  The advantage of this
> >model over the one-dimensional one is that it accurately predict
> the contact
> >surface temperature of the circuit-tubing and the adjacent
> medium, required
> >to compute the boiler/chiller power, and the minimum and maximum
> >ceiling/floor temperatures, required for local moisture condensation
> >(ceiling cooling systems), thermal discomfort (heating floor systems) and
> >controls.  The model predictions for slab-on-grade heating
> systems compared
> >very well with the results from a full two-dimensional numerical model.
> >
> >The model was implemented in the Canadian software HOT3000 and the UK
> >software ESP-r as a plant component. The implementation of this
> model in the
> >ESP-r program offers additional flexibilities to the radiant
> system designer
> >community, mainly:
> >·       Designers can use any control algorithm possible in
> ESP-r with the
> >new plant component (e.g.., use the flux or temperature control,
> and compare
> >their performance).
> >·       Designers can specify any number of radiant surfaces of
> the building
> >fed by the same or different heat source.
> >·       Designers can size realistic radiant systems, and get realistic
> >energy consumption (from the source side) and cost.
> >
>

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