For cooling, the ChillerHeater:Absorption:DirectFired class has performance curve fields that allow cooling COP and cooling capacity to vary with temperature (see Fuel Input to Cooling Output Ratio Function of Temperature Curve Name and Cooling Capacity Function of Temperature Curve Name).

However, for heating-only operation, there are no fields that allow heating COP or heating capacity to vary with temperature. Is there a workaround to allow this?

My gas-fired absorption chiller will only provide heating, it has no turndown ability (Minimum Part Load Ratio is 1), and its heating COP varies with temperature.

I am able to implement my desired heating capacity and heating COP at full load via the Nominal Cooling Capacity, Heating to Cooling Capacity Ratio, and Fuel Input to Heating Output Ratio fields, but I don't see a way to vary heating capacity or heating COP with temperature.