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Introduction to EN 15316-1

Overview

EN 15316-1 (equivalent to EN 15316-1 in Europe) defines the framework and general principles for calculating the energy performance of building heating and domestic hot water systems.
It provides a systematic, modular approach that allows engineers, researchers, and software tools to evaluate and compare energy efficiency across different system configurations.

This standard is part of the broader Energy Performance of Buildings (EPB) suite developed under the EU Energy Performance of Buildings Directive (EPBD).

Scope

The standard covers water-based heating and DHW systems where heat is generated, distributed, and emitted to maintain indoor comfort.
It applies to: - Emission systems (radiators, floor heating, fan coils, etc.) - Distribution systems (piping, manifolds, circulation) - Storage components (thermal buffers, DHW tanks) - Generation systems (boilers, heat pumps, cogeneration)

It does not include ventilation-only or purely air-based systems, except when heated by water circuits.

Methodological Structure

EN 15316-1 introduces a modular structure, dividing the entire heating system into interconnected subsystems:

  1. Emission (C.2–C.5) – heat transfer from water to the indoor space
  2. Distribution – transport of heat through pipes, including losses and auxiliaries
  3. Storage – intermediate energy buffering or recovery
  4. Generation – production of useful heat from a fuel or electricity source

Each module has its own energy balance:

\[ \text{Energy In} = \text{Useful Output} + \text{Losses} - \text{Recoverable Losses} - \text{Auxiliaries} \]

The calculation proceeds in the direction:

\[ \text{Energy Needs (Building)} \rightarrow \text{Delivered Heat (Emission)} \rightarrow \text{Distribution} \rightarrow \text{Generation} \rightarrow \text{Primary Energy Input} \]

This enables transparent energy tracking and consistent efficiency assessment across technologies.

Objectives

The main objectives of EN 15316-1 are to: - Provide a consistent calculation structure for all sub-systems in heating and DHW installations.
- Define input and output data exchange between modules.
- Enable comparability between different system types (e.g., boilers vs. heat pumps).
- Serve as the reference method for EPB-compliant national calculation procedures.

Key Principles

  • System boundary definition – explicit separation of emission, distribution, storage, and generation.
  • Energy flow consistency – all sub-systems connect via clear input/output relationships.
  • Recoverable vs. non-recoverable losses – internal gains can offset building demand.
  • Auxiliary energy – electric or mechanical support energy is always accounted for.
  • Adaptability – compatible with both monthly and hourly calculation time steps.

Benefits

  • Harmonized methodology for energy performance certificates, design tools, and research.
  • Facilitates diagnostic comparison of subsystems (e.g., identifying excessive distribution losses).
  • Supports policy implementation under EPBD and national building codes.
  • Enhances reproducibility and transparency in simulation and benchmarking.

Relationship with Subsequent Parts

Part 1 provides the general framework only.
Detailed formulas and reference values for each sub-system are defined in:

  • EN 15316-2 – Emission and control (M3-5)
  • EN 15316-3 – Distribution and control (M3 -6)
  • EN 15316-4 – Generation systems (M3-8) for different generator:
    • EN 15316-4-1 – Combustion boilers (M3-8-1)
    • EN 15316-4-2 – Heat pumps (M3-8-2)
    • EN 15316-4-3 – Thermal solar and photovoltaic (M3-8-3)
    • EN 15316-4-4 – On-site cogeneration (M3-8-4)
    • EN 15316-4-5 – District Heating and Cooling (M3-8-5)
    • EN 15316-4-9 – Direct electrical heater (M3-8-6)
    • EN 15316-4-8 – Radiant heating and stoves (M3-8-8)
  • EN 15316-5 – Storage and control (M3-7)

References

  • EN 15316-1:2017 – Energy performance of buildings — Method for calculation of system energy requirements and system efficiencies — Part 1: General and energy performance expression.
  • REHVA (2017) — Information Paper: CEN Standards for Heating and Domestic Hot Water Systems.
  • CENSE Project (EU) — Application of the EPBD Calculation Framework.