Add technology that produces low-temperature heat (to be used by lt-heat pump) assuming that air temperature is above threshold. [Theoretically, one should model COPs. Practically, probably just setting T_air > 20 or 25 or good enough to ensure that the heat obtained from the air as good as "low-temperature waste heat" as it is available from data or distribution centers. Importantly, by adding this technology, it becomes possible to use one heat pump to both use waste heat and air-source (but the air only at high enough temperatures, which is unrealistic. Therefore, this needs some thinking.
Add technology that produces low-temperature heat (to be used by lt-heat pump) assuming that air temperature is above threshold. [Theoretically, one should model COPs. Practically, probably just setting T_air > 20 or 25 or good enough to ensure that the heat obtained from the air as good as "low-temperature waste heat" as it is available from data or distribution centers. Importantly, by adding this technology, it becomes possible to use one heat pump to both use waste heat and air-source (but the air only at high enough temperatures, which is unrealistic. Therefore, this needs some thinking.