What's the typical mean radiant temperature setpoint/schedule for radiant floor heating system

asked 2016-03-11 21:08:16 -0600

Hyphen32
121 ●4

updated 2016-03-15 09:25:04 -0600

Jason DeGraw

2208 ●6 ●10 https://github.com/jasondegraw

Hi everyone,

I am doing a simulation for a radiant floor heating system. Now I am using a template found in BCL(by apply measure). The HVAC template I used named AEDG Office HVAC radiant DOAS. Now the schedule for the thermostat is 18.3 C to 18.9. My question is when I run the simulation in E+, the variable shows the mean temperature would be below 18, sometimes to 15 C in this case. I dont know why. Beside what's the typical setpoint for the mean radiant temperature of a residential building?

Comments

@Hyphen32 please add a tag for the software you're using.

MatthewSteen ( 2016-03-12 07:59:48 -0600 )edit

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answered 2016-03-12 13:58:19 -0600

Annie Marston
4317 ●5 ●32 http://www.resustain.com

There are two things to consider here. The thermostat setpoints, which are air temperature setpoints and the temperature setpoints in the radiant floor component itself (along with the deadband delta T) I have found when investigating comfort in a room using mean radiant temperature as a measurement variable that the temperatures in the component itself should be 0.5C higher for heating than the thermostat setpoints. This way the rooms maintain fairly even temperature. For our projects the acceptable temperatures within the space are usually anywhere between 20 - 26C.

There are a few reasons why your floors are not meeting setpoint temperature in your model.

The floors are not sized correctly, ie the flow rate through them is not high enough or the temperature of the water flowing through them is not high enough (for heating)
The construction of your floor might be limiting the amount of heat that is able to radiate into the space. if you have insulation above your pipes for instance, the heat can not pass through the construction to effectively heat the space.
There might be another component in the space (such as fresh air or AHU) that is delivering cold air to the space whilst the floors are trying to heat the space and there is not enough capacity in the floors to meet the load. (zone sizing component and setpoint manager components are a good place to look for this issue)