ISO 52031:2020

Overview

ISO 52031:2020 - Energy performance of buildings - Method for calculation of system energy requirements and system efficiencies - Space emission systems (heating and cooling) defines the structure, required inputs and outputs for calculating energy requirements and efficiencies of space emission systems. It applies to heating systems and water‑based cooling space emission sub‑systems, and is part of the EPB (energy performance of buildings) family of standards that support consistent, transparent building energy assessments.

Key topics and technical requirements

• Scope and structure: Specifies the calculation method’s required inputs, outputs and links (structure) for space emission systems (emitters and embedded emitters).
• Main outputs: Energy losses (heating and cooling) Q_em,ls; auxiliary energy W_em,ls,aux; equivalent internal heating/cooling temperatures (θ_int,inc); temperature variation Δθ; and related performance factors.
• Time resolution: Outputs can be calculated at hourly, monthly or yearly time steps depending on input data.
• Input categories:
  • Product / technical data (emitters, hydraulics, pumps, fans)
  • Configuration and system design data (layout, emitter types, embedded systems)
  • Operating or boundary conditions (control set‑points, schedules)
  • Data sources and references (normative templates in Annex A/B)
• Physical effects covered: Non‑uniform temperature distribution, emitter losses (including those embedded in structures), control accuracy and operation, stratification and radiant/convective fractions (RF, convective fraction).
• Energy accounting: Separately calculates thermal energy and electrical auxiliary energy to enable final and primary energy conversions.
• Templates and defaults: Normative Annex A provides a template for specifying choices and inputs; Annex B contains informative default choices and references.

Practical applications and target users

Who uses ISO 52031:2020:

• HVAC and building services engineers performing design optimization and system sizing.
• Energy assessors and modelers calculating additional heating/cooling losses and system efficiencies for EPB compliance.
• Software developers building energy simulation or compliance tools that require standardised input/output structures.
• Policy makers, certifiers and researchers needing harmonised methods to compare system-level performance across projects or jurisdictions.

Typical uses:

• Quantifying additional energy losses due to emission system inefficiencies.
• Comparing alternative emitter or control strategies during system design optimization.
• Feeding system‑level losses into whole‑building EPB calculations.

Related standards

• ISO 52000‑1 (overarching EPB assessment - framework and procedures)
• ISO 7345 (thermal performance - quantities and definitions)
• Relevant regional standards cited in EPB modular frameworks (for example EN 15316, EN 12831) - consult national/regional guidance for integration.

Keywords: ISO 52031:2020, energy performance of buildings, space emission systems, heating and cooling, calculation method, system energy requirements, auxiliary energy, emitters, embedded emitters, EPB standards.