Innovative load sharing mechanism through active slab - modeling challenges

Recently I came across an interesting “load sharing” mechanism via a thermally active slab that I am trying to model using Honeybee/E+, but I have not found a satisfactory way of doing so.

The main idea is that always having water flowing in the pipes imbedded in the slab is equivalent to having a highly conductive slab, so zones where the slab temperature is high effectively transfer excess heat to the zones where the slab temperature is low. In this manner, zones that would be under cooling transfer thermal energy to the zones that are in heating, thereby reducing/eliminating the heating load at the central plant (for this application the slab is for heating only). The key is having that constant flow of water throughout all the thermal zones of the slab/space, regardless of whether they are in cooling or in heating. (For this system all the zones are in “parallel” with each other, and all would receive water at 32 C if all zones are under heating, but would only circulate water, without central plant heat addition, through all the slab zones if any zone is in cooling, letting the load sharing mechanism deal with the heating load).

The problems I am running into are:

  1. E+ won’t want to run water through a low temp. radiant heating coil if the zone is not in heating
  2. Even if flow is “forced” through that coil and, I am not sure E+ will transfer heat from the zone into the coil, as it is expecting the heating coil to move energy into the slab/zone, but not gain energy from them.

I was hoping to see if y’all have an idea of how to simulate this system, or maybe how to deal with the two problems I described. Above all my aspiration is to simulate the process of an ambient temperature loop transferring energy between core and perimeter zones in a heating-load dominated climate through this effect. Of course I am open to any and all creative approached to representing this phenomenon.



This is a very interesting modeling scenario. Since it seems like you haven’t gotten any responses to this query, I would recommend you escalate this question to the Unmet Hours forum. This is really a E+ problem rather then a Honeybee problem at this point. We can always help you implement the resulting E+ in Honeybee if necessary. And it’d be great if you can share the correct way to implement this back here, once you do get a response!