Start with the required heat
Heating an office building, supplying hot water or providing heat for a production process: these tasks require different temperatures and operating hours. A heat pump should therefore not be selected solely on the basis of past gas bills. The bill records fuel purchased; planning requires the amount of heat actually needed, how it is distributed and the required temperatures.
Discuss with your specialist planner which heat source is available and how it matches the intended use of the heat. For industrial processes, Fraunhofer ISE provides guidance on selecting high-temperature heat pump technologies. The choice depends, among other things, on the temperature of the available source and the temperature required by the process or heating system. These two figures should therefore be established at the start of the planning discussion.
Estimate an initial amount of electricity in a comprehensible manner.
The performance factor indicates how much heat a heat pump supplies per kilowatt-hour of electricity used over the period considered. A factor of 3 means that 1 kWh of electricity, together with the heat absorbed from the source, produces a total of 3 kWh of usable heat. For an initial estimate, divide the amount of heat required by the expected performance factor.
A performance factor of 3 is an assumption for this calculation, not a forecast for your site. Supplying the same amount of heat with a performance factor of 2.5 would require 120,000 kWh of electricity. This range shows why the assumption used for procurement needs a sound basis.
Do the amount of heat supplied and the electricity consumption refer to the same system? Pumps, auxiliary drives and electric backup heating must not be accidentally omitted or counted twice.
The coefficient of performance (COP) is the ratio of heat output to electrical power input at a particular operating point, for example with specified source and flow temperatures. This instantaneous value does not replace a seasonal performance factor measured in actual operation or reliably forecast. For your budget, assess several justified assumptions rather than one particularly favourable value.
Also check the timing and power demand
Space heating demand is highest during the colder months. At the same time, production, lighting, and charging points may also require electricity. Therefore, an additional annual consumption figure provides little information about the overall peak demand. Clarify connection capacity, metering concept, and any necessary grid modifications early on.
- What electrical power is required during normal operation?
- When do backup heating or other heat generators operate?
- Which electrical loads are already running at those times?
- What shift is possible without affecting heat supply and operation?
Consider the supply contract before the changeover.
Inform procurement managers about commissioning, the expected additional volume and the new profile. A system starting only in October should not enter the current-year forecast with a full annual volume. For space heating, even a flat quarter of the annual volume is unsuitable because heating months have higher demand. Have the expected consumption after the planned start calculated using seasonal heat demand. Delays and a gradual ramp-up should also be visible.
Check the provisions for higher or lower consumption in your electricity contract. A separate heat pump tariff or a particular network charge arrangement does not automatically apply to every commercial installation. Metering, the connection and the applicable requirements must all be compatible.
Assess the investment and energy procurement together
Compare the total running costs, including remaining fuel costs, auxiliary energy, and maintenance. Subsidies should only be included in the calculation once the eligibility requirements have been clarified. The structure in the article on the Energy Budget for Companies helps to keep assumptions transparent.
Discuss future electricity supply with OPTUM: Have the planned start date, your current supply volume and the assumptions of the specialist planning ready.
