Heating degree days / cooling degree days

[l-emele]

Description of the issue

Heating and cooling degree days are important concepts to describe heating and cooling demand of buildings.

Ideas of solution

If you already have ideas for the solution describe them here

Workflow checklist

• [ ] I discussed the issue with someone else than me before working on a solution
• [ ] I already read the latest version of the workflow for this repository
• [ ] The goal of this ontology is clear to me

I am aware that

• [ ] every entry in the ontology should have a definition
• [ ] classes should arise from concepts rather than from words

[l-emele]

Eurostat's definitions:

• Heating degree day (HDD) index is a weather-based technical index designed to describe the need for the heating energy requirements of buildings.
• Cooling degree day (CDD) index is a weather-based technical index designed to describe the need for the cooling (air-conditioning) requirements of buildings.

[wingechr]

a little further down, the definition is a bit more detailed, including the reference temperature

• Heating Degree Days (HDD) index: the severity of the cold in a specific time period taking into consideration outdoor temperature and average room temperature (in other words the need for heating). The calculation of HDD relies on the base temperature, defined as the lowest daily mean air temperature not leading to indoor heating. The value of the base temperature depends in principle on several factors associated with the building and the surrounding environment. By using a general climatological approach, the base temperature is set to a constant value of 15°C in the HDD calculation.

• Cooling degree days (CDD) index: the severity of the heat in a specific time period taking into consideration outdoor temperature and average room temperature (in other words the need for cooling). The calculation of CDD relies on the base temperature, defined as the highest daily mean air temperature not leading to indoor cooling. The value of the base temperature depends in principle on several factors associated with the building and the surrounding environment. By using a general climatological approach, the base temperature is set to a constant value of 24°C in the CDD calculation.

[l-emele]

Not much happened here in recent time. Part of that part because HDD and CDD are a bit a weird concepts.

My current thought is that HDD and CDD are process attributes of heating and cooling demands. Heating and cooling demand themselves are still missing, but we should include them. I see them as energy service demand subclasses:

• heating demand: A heating demand is an energy service that manifests in keeping a constant temperature or increasing the temperature (target temperature) under a condition where the outside temperature is lower than the target temperature.
• cooling demand: A cooling demand is an energy service that manifests in keeping a constant temperature or decreasing the temperature (target temperature) under a condition where the outside temperature is lower than the target temperature.

Then HDD and CDD can become process attributes of these energy services:

• heating degree days: Heating degree days (HDD) are a process attribute that describe a heating demand.
• cooling degree days: Cooling degree days (CDD) are a process attribute that describe a cooling demand.

Might be easier if we define heating and cooling first:

• 1595