ISO 13612-2:2014

Overview

ISO 13612-2:2014 - Heating and cooling systems in buildings - Part 2: Energy calculation - defines a steady-state method for calculating the energy performance of heat pump systems used for space heating, space cooling and domestic hot water (DHW). The standard provides a single-step calculation routine whose results are intended to be incorporated into larger building energy models. It covers electrically driven vapour-compression cycle (VCC) heat pumps, combustion-engine driven VCC, and thermally driven vapour absorption cycle (VAC) heat pumps, including combinations of heat sources and distribution types (outdoor air, exhaust air, ground/water sources, DX/VRF, etc.).

Key topics and requirements

• Scope of calculation: steady conditions corresponding to one calculation step (hour, month, bin or season) to represent energy use for heating, cooling and DHW.
• Inputs and outputs: specifies required input data (product performance characteristics, external conditions, control settings) and required outputs for thermal power generation and energy use.
• System boundary and schematization: defines what is included in the generation subsystem and how the heat pump is represented for heating, cooling and DHW modes.
• Performance metrics: uses COP (coefficient of performance) and effective power input; includes procedures for tabulated COP values and interpolation/part-load handling.
• Auxiliary energy: clarifies auxiliary vs driving energy (fans, pumps, controls) and how these are counted in the calculation.
• Loss accounting: procedures for recoverable, recovered and unrecoverable heat losses from the generation subsystem and generator envelope.
• Operational factors: calculation of running time, backup heaters, cut-out periods and control interactions.
• Annex material: informative annexes include COP matrix construction, interpolation methods, part-load COP calculations, a BEST program model, and energy evaluation for combined or special HPWH and combined systems.

Applications and users

ISO 13612-2:2014 is intended for:

• HVAC and building services engineers performing heat pump energy calculations and system design verification.
• Energy modelers and consultants integrating heat pump generation performance into whole-building energy performance assessments.
• Manufacturers and test labs translating product performance data (COP, capacity) into system-level energy outcomes.
• Regulators and certification bodies assessing compliance with energy targets and comparing system options. Practical uses include compliance checks, optimisation of heat pump configurations, comparison of alternative heat sources/distributions, and evaluation of energy conservation measures.

Related standards

• ISO 13612‑1 - Design and dimensioning (complements Part 2)
• ISO 13790 - Building energy calculation methods
• ISO 13675 - Combustion systems (boilers) energy calculation methods
• EN ISO 7345, ISO/TR 16344 - supporting terms, definitions and thermal quantities

Keywords: ISO 13612-2:2014, heat pump energy calculation, COP, HPWH, building energy modelling, auxiliary energy, heat pump systems.