TCP, space loss and time loss calculation method

grasshopper honeybee-legacy
1

Hi @chris
Can you please explain how do you calculate avg. , space loss and time loss for the dimension less metric of Thermal Comfort Percent (TCP) ?
Thank you in advance

Hardi

2

Occupied Thermal Comfort Percent (occTCP) is defined at the percentage of occupied hours where conditions at a given location are within the acceptable ranges of the comfort model.

For the Honeybee computation of TCP as you see here, the occupied period is determined by the HBZone occupancy schedule (any time that the occupancy is above 0 by default). The acceptable ranges of the comfort model depend on which comfort model you are using. The default for a PMV map is to have < 10% PPD in order to be comfortable. The default for the adaptive comfort map is to have < 2C from the target temperature to be comfortable. All of these characteristics of the comfort model can be changed if your occupancy period is different or if you want to use different criteria for acceptable conditions.

If you want to describe the “space lost” due to uncomfortable conditions, you will have to come up with a value where, if there’s a certain percentage of occupied hours where the conditions are not comfortable, this floor area is not considered usable. There’s no standard for this right now but I have seen people use values ranging from 10% uncomfortable hours to 50% uncomfortable hours depending on how important thermal comfort conditions are to the space in question.

3

Thank you for the reply chris,

First, I use adaptive model to thermal performance evaluation.

  • I know all of that, but I was not sure about the best way to calculate the “space lost” and still not fully get the idea!
    Can I use operative temperature map and define the degrees above upper temp bound of the adaptive range? If so, how can I precisely catch those mesh squares and obtain the exact discomfort area?

  • For the “hours lost”, for example if I have 3650 available office working hours and 3580 comfortable hours, in this case the number of hours lost will be (3650 - 3580 = 70 hours), am I right?

Hardi

4

@HardiBarznji ,

  1. I think you want to use the occTCP results and not the operative temperature. You can change the acceptable degrees from the target temperature using the Adaptive Comfort Parameters component as an input for the adaptive comfort recipe (before you run the comfort map). The component really only has options for 90% or 80% PPD (2 degrees or 2.5 degrees from the target) since these are the only options available in the thermal comfort standards. If you really need to do custom stuff with the data, you can check the output csv files or convert the matrices to grasshopper data trees using the Matrix to Data Tree component. You can select the regions of a mesh that meet certain criteria using the Mesh Threshold Selector.

  2. I not sure what you are referring to here. Is this question still about microclimate maps?

5

Alright, I understood the first point.
Yes, I want to calculate the number of “hours lost” for TCP. I think mentioning the “space lost” and “hours lost” is best option to clarify the results of TCP.
Also, is there a method to know Average TCP? Does the ResultValues output of the Honeybee_VisualizeMicroclimateMap component represent this?

Another question; when a zone is only naturally-conditioned TCP (of the analyzemicroclimatemap component) is still different from occTCP (of the thermalautonomy component)?

Thanks