ISO/PRF TS 23764

Methodology for achieving non-residential zero-energy buildings (ZEBs)

Titre manque

General Information

• Status: Published
• ICS: 91.040.01 - Buildings in general
• Technical Committee: ISO/TC 205 - Building environment design
• Drafting Committee: ISO/TC 205/WG 2 - Design of energy-efficient buildings
• Current Stage: 1020 - New project ballot initiated
• Start Date: 31-Jan-2020

Standards Content (sample)

TECHNICAL ISO/TS
SPECIFICATION 23764
First edition
Methodology for achieving non-
residential zero-energy buildings
(ZEBs)
PROOF/ÉPREUVE
Reference number
ISO/TS 23764:2021(E)
ISO 2021
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ISO/TS 23764:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
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ISO/TS 23764:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Stepwise approach toward ZEB ............................................................................................................................................................. 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Planning phase ........................................................................................................................................................................................ 3

4.2.1 Determining the ZEB stage target: ZEB-ready, nearly ZEB, or (net) ZEB ........................ 3

4.2.2 Reference primary energy consumption and reduction rate targets ................................. 4

4.3 Design phase ............................................................................................................................................................................................. 5

4.3.1 General...................................................................................................................................................................................... 5

4.3.2 Setting the outcome ...................................................................................................................................................... 5

4.3.3 Passive design..................................................................................................................................................................... 6

4.3.4 Active design........................................................................................................................................................................ 6

4.3.5 Selection of building materials, equipment and systems ............................................................. 7

4.3.6 Forecast of primary energy consumption and energy supply for attaining

the targets .............................................................................................................................................................................. 9

4.4 Construction phase ............................................................................................................................................................................. 9

4.4.1 General...................................................................................................................................................................................... 9

4.4.2 Construction plan ............................................................................................................................................................ 9

4.4.3 Construction and inspection...............................................................................................................................10

4.4.4 Final check and verification (as built) ........................................................................................................10

4.5 Operations and management ..................................................................................................................................................10

4.5.1 Fine tuning .........................................................................................................................................................................10

4.5.2 Understanding the primary energy consumption ...........................................................................10

4.5.3 Comparison between planned primary energy consumption and actual

measurements.................................................................................................................................................................10

4.5.4 Optimizing the energy consumption ...........................................................................................................11

4.5.5 Measurement and feedback ................................................................................................................................11

5 Examples of evaluations on ZEB ........................................................................................................................................................11

Annex A (informative) Example of (net) ZEB evaluation ..............................................................................................................12

Annex B (informative) Example of a nearly ZEB evaluation ......................................................................................................22

Annex C (informative) Example of ZEB-ready evaluation ............................................................................................................30

Bibliography .............................................................................................................................................................................................................................37

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ISO/TS 23764:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 205, Building environment design

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/TS 23764:2021(E)
Introduction

This document aims to apply a methodology for achieving a zero-energy building (ZEB).

Since the Paris Agreement was adopted in the 21st Session of the Conference of the Parties to the

United Nations Framework Convention on Climate Change, all member countries (including emerging

countries) have been required to set a target for reducing their greenhouse gas emissions by 2020

and later. In all countries, reducing energy consumption is the most effective means of mitigating

greenhouse gas emissions.

The building sector takes a 30 % share of the world’s energy consumption, and this contribution appears

[8]

to be increasing . Therefore, reducing the greenhouse gas emissions from this sector is an important

global issue. Ultimately, the energy consumption of the building must be reduced and balanced by

renewable energy to create a (net) ZEB. Such advanced cases have already been constructed.

Although the ultimate goal of achieving ZEBs is clearly understood, its realization has been limited by

practical barriers such as high initial investment. However, as the life cycle of buildings is long, the

design and construction of more energy-efficient buildings is considered as a present attempt rather

than a future one for greenhouse gas reduction. Hence, accelerating the movement toward ZEBs is an

immediate urgency.

From this perspective, this document advocates a step-by-step realization approach for (net) ZEBs.

Its aim is to accelerate the ZEB movement and describe the practical realization of ZEBs. Namely, this

document proposes a practical ZEB approach and outlines the basic considerations during the complete

process of ZEB realization, from design to the operation and maintenance stages.

To accelerate the reduction of greenhouse gases, this document aims to contribute policies and/or

guidelines for disseminating ZEBs that suit the conditions of individual countries, especially those of

emerging countries undergoing rapid urbanization.

To assist understanding of the contents of this document, the following four ZEB examples are included

as annexes:

— (net) ZEB results of evaluating a ZEB renovation of an actual use office building (see Annex A);

— nearly ZEB results of evaluating a ZEB city hall encompassing regional history, climate, and

1) 2)
resources (see Annex B);
— ZEB-ready model of an urban medium-sized office (see Annex C).

1) Net Zero Energy Buildings International Projects of Carbon Neutrality in Buildings (IEA SHC)

2) Three examples toward realizing ZEB were selected from the Net Zero Energy Building Advanced Case Collection

published by The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan (SHASE);

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TECHNICAL SPECIFICATION ISO/TS 23764:2021(E)
Methodology for achieving non-residential zero-energy
buildings (ZEBs)
1 Scope

This document provides a basic step-by-step approach for achieving non-residential (net) zero-energy

buildings (ZEBs). It also describes the basic concept of ZEBs and the items for consideration in this

approach.
The following are within the scope of this document:
— application to non-residential buildings;

— annual energy consumption of a ZEB (this includes the operating consumption of the building and

excludes the energy consumed by the manufacturing of materials and equipment, and the energy

consumed during construction);

— renewable energy supply (this can be on-site or off-site, depending on the policy and conditions of

the country in which the supply is installed);
— application to any climate zone.
The following are out of the scope of this document:

— recommendations or suggestions for the adoption of any specific technologies and/or equipment

and materials that are expected to be continuously innovated (however it does stipulate the

technologies for selection);
— specific methods or calculation formulae;
— commissioning methods.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 50001:2018, Energy management systems — Requirements with guidance for use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org
NOTE The terms defined in this clause are detailed in 4.1.
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3.1
ZEB-ready

building that prospectively achieves (net) ZEB (3.3) through enhanced insulation suited to building use

and climate, exterior surface and shading for suppressing the load, high-efficiency energy-conservation

equipment and optimization of energy consumption by data integration and verification

3.2
nearly ZEB

building that almost achieves (net) ZEB (3.3), with an annual primary energy consumption of almost

zero using renewable energy while meeting the criteria of ZEB-ready (3.1)
3.3
(net) ZEB

building with zero or negative net annual primary energy consumption while meeting the criteria of

ZEB-ready (3.1)
4 Stepwise approach toward ZEB
4.1 General

The stepwise approach toward ZEB from ZEB-ready to (net) ZEB follows a plan⟶ do⟶ check⟶ act

(PDCA) process that is consistent within many standards. This process is explained in Figure 1.

Figure 1 — Key process for achieving ZEB – PDCA (Plan, Do, Check, Act)

This clause describes this approach in detail in consideration of six core elements listed in Figure 2.

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Figure 2 — Six core elements for achieving non-residential ZEBs
4.2 Planning phase
4.2.1 Determining the ZEB stage target: ZEB-ready, nearly ZEB, or (net) ZEB

In general, achieving a (net) ZEB requires a sharp reduction in energy consumption, without the

reduction in quality of the indoor and outdoor environments, with the inclusion of renewable energy to

offset the remaining energy consumed through the building activities.

The planning and design of a ZEB requires the generation and use of renewable energy. However, this

should be considered after reducing the energy consumption as far as possible by a passive design

approach, an active design approach including selection of energy-efficient active systems, and

deployment of energy management systems that facilitate optimized building energy performance.

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Immediately achieving a (net) ZEB may be prevented by regional and climatic circumstances, building

typology, and other circumstances beyond the project team’s control. To accommodate these limitations,

this document adopts a three-tiered nomenclature for ZEB:
a) A ZEB-ready building meets the following condition:

— The primary energy consumption is reduced by a predetermined amount (α%) or more from

the reference primary energy consumption, excluding renewable energy.
b) A nearly ZEB building meets both of the following conditions:

— The primary energy consumption is reduced by a predetermined α% or more from the reference

primary energy consumption, excluding renewable energy.

— The primary energy consumption is reduced by β% or more (less than 100 %) from the reference

primary energy consumption, including renewable energy.
c) A (net) ZEB meets both of the following conditions:

— The primary energy consumption is reduced by a predetermined α% or more from the reference

primary energy consumption, excluding renewable energy.

— The primary energy consumption is reduced by 100 % or more from the reference primary

energy consumption, including renewable energy.
4.2.2 Reference primary energy consumption and reduction rate targets

The reference primary energy consumption (EP0) in Figure 3 should be calculated by adding the primary

energy consumption of the air conditioners, ventilators, lighting equipment (including task lighting),

hot water supply equipment, the elevators and escalators, and other energy consuming equipment in

the building. This shall be calculated according to the energy efficiency standards of buildings, while

considering the climatic impact on the construction site. The annual primary energy consumption per

unit of floor area and the floor area in a standard model building may be used to calculate the reference

primary energy consumption in different countries. When appropriate, the reference primary energy

should be revised in accordance with technological advancements on building materials and energy-

efficient equipment, and with the level of maturity of the energy-conservation scheme.

Reduction rate targets for primary energy consumption should be determined in the three stages: ZEB-

ready, nearly ZEB, and (net) ZEB. The energy-efficiency improvement should first support equipment

that consumes energy (toward ZEB-ready). Once that target has been met, the total primary energy

consumption should be reduced by encouraging electric-power generation from renewable energy

sources.
Target of α% for ZEB-ready ≦ (1 − EP /EP ) × 100
cal 0
Target of β% for nearly ZEB ≦ (1 − (EP − EP )/EP ) × 100
cal gen 0
Target for (net) ZEB, 100 % ≦ (1− (E − EP )/EP ) × 100
cal gen 0
where
EP is the reference primary energy consumption (MJ/year);
EP is the primary energy consumption (MJ/year);
cal
EP is the energy supply (renewable energy) volume (MJ/year).
gen

Primary energy consumption is annual consumption and is not defined in detail in this document.

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The reduction-rate targets α% and β% should be set by individual countries, although β should be

larger than α. Multiple α and β values may be set at different levels.

The reference primary energy consumption EP , the target values of α and β, and other parameters may

be revised in accordance with technological advancements.
Key

The target of the energy consumption reduction from the reference primary energy consumption is set in

accordance with regional circumstances and adopted as a standard.

A reference building may be determined in accordance with regional circumstances and its energy consumption

is defined as the reference energy consumption.
Reduction rate targets, α% and β% to be set by individual countries.
Figure 3 — Energy supply versus energy consumption
4.3 Design phase
4.3.1 General

An evaluation method for energy performance equivalent to ISO 52000-1 can be used. The matters

stated below should be considered for specific design methods.
4.3.2 Setting the outcome

Defining the project’s performance at the briefing stage is important. If the constraints on and

opportunities for setting design goals for environmental sustainability are considered at the onset

of a building project, a holistic total building performance is ensured. Thus, feasibility studies and

assessments of the available options and benchmarking of similar projects provide the project team

with a realistic grounding of the achievable ZEB level.
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The project brief formalizes the sustainability targets and estimates the building lifespan and

operational cycles. Early consultations and studies ensure that the targets are achievable and that the

post completion goals (against which the building will be judged) are clearly stated.

An integrative design process encourages a collaborative framework for setting the building-

performance benchmarks and targets. Through this process, the project team is obliged to regularly

review the design goals across disciplines and can address and negotiate among the various needs of all

stakeholders to achieve the ZEB target.
4.3.3 Passive design

Passive strategies are fundamental in the design of energy-efficient buildings, as they maximize the

climatic response to the site context, reduce the load on “active systems,” and provide a comfortable

indoor environment. The typical passive-design principles are as follows (the list is non-exhaustive):

— building orientation, massing and form;
— building envelope and material selection;
— use of natural ventilation;
— maximum use of free heating or cooling;
— design of daylighting (while minimizing visual discomfort).
4.3.4 Active design
4.3.4.1 Energy users

Typical active systems or building services are mechanical systems, e.g. air conditioning, heating,

mechanical ventilation, lighting, vertical transportation, pumping, and other unregulated energy

source equipment, which provide the bulk of the energy consumption in a building. The focal strategies

for achieving a low energy building are as follows (the list is non-exhaustive):

— Correct sizing of equipment such as air-conditioning systems and heating systems:

This strategy ensures the proper allocation of the building loads, avoiding over- or under-provision

that would reduce the operational efficiency.
— Selection of high efficiency systems and technologies:

Adoption of high-efficiency equipment, e.g. lighting, heating, and cooling systems, mechanical

ventilation systems, vertical transportation systems, hot water systems. Equipment should be

energy-labelled and provided with certified (tested) performance data. The control systems using

sensors are also applied for those types of equipment.
— Selection of systems with high efficiency over the operational range:

For example, air-conditioning systems should operate with high efficiency over a range of loads

under capacity control, e.g. inverter technology for the compressors. Fans and pumps should

operate under variable flows and speeds.
— Use of energy recovery systems:

Converting waste energy to useful energy reduces the load on other systems. An example is heat

recovery for air conditioning or heating systems.
4.3.4.2 Energy management system

A building or energy management system (BMS) can monitor and manage all mechanical and electrical

services in a building. These systems improve the energy efficiency by tailoring the appliances to real

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needs and saving operation and maintenance costs while improving the occupancy comfort. Among

the fastest-growing and dynamic ZEB-focused technologies are smart building technologies. By tapping

into the Internet of Things, advanced sensors, and big data analytics, smart technologies have shown

potential for significant savings through demand control, optimization, and predictive maintenance.

Strategies for energy management systems include the following (the list is non-exhaustive):

— Energy monitoring and visualization:

This strategy provides occupants with an easy, accessible visualization of the energy consumption

indices by area and the use/load, trend, cost, and target/benchmark. Related to this ideal of openly

sharing the building data, open standards are required to future-proof the building’s management

system and to facilitate data exchange between subsystems. Furthermore, if the end users can

access the monitored information, they are more likely to partake in engagement programs and

make behavioural changes.
— Demand control systems:

Occupancy-based controls can match the building services to the building use, facilitating energy

savings and optimization of systems while maintaining high indoor environmental quality. For

example, demand control ventilation strategies such as carbon dioxide sensors will help regulate

the quantity of fresh air and ventilation in accordance with the space requirements.

— Integration and analytical systems:

These systems integrate the sensor data for optimizing the workflow or maintaining high

performance and energy efficiency in a building, providing an informed and effective operation

in the building. By using automation data and behavioural science, building professionals can

optimize the equipment and their related processes to maintain the equipment efficiency and

building comfort requirements.
4.3.4.3 Renewable energy

Renewable energy sources are required to generate or offset the energy used by building systems.

Renewable energy sources include (but are not limited to) solar (photovoltaics) and wind power.

4.3.5 Selection of building materials, equipment and systems
4.3.5.1 General

The building materials, equipment, and systems should be selected in the design phase. The selected

items should have obtained performance certification, e.g. energy efficiency certification, appropriate

to the regional circumstances, or which conform to the standards in the country of construction. To

meet ZEB targets, high-efficiency equipment and systems are required.

To achieve an overall balance, the selected materials, equipment, and systems should also optimize the

costs.
4.3.5.2 Selection of building materials
— Load reduction

— Enhancement of the thermal insulation for the exterior surface of the building and control for

solar radiation.

— Selection of the materials with high thermal insulation performance for the exterior walls,

roofs, floors, windows, and other openings.
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— Introduction of the items that properly control the solar radiation from windows (glazing with

excellent shading performance, window shades, eaves and the equivalent).
— Use of natural energy
— Utilization of natural ventilation.
EXAMPLES automatic windows, opening of ceiling spaces by the stack effect.
— Utilization of daytime sunlight.

EXAMPLES construction of openings, neighbouring buildings, and topographic features on the

sunlight side, light shelves, light duct systems.
4.3.5.3 Selection of equipment and systems
4.3.5.3.1 Air-conditioning equipment
— Selection of heat-source type:
The heat-source system can be centralized or distributed.

— Selection of a model with high partial-load properties that adjusts the partial load efficiency in

accordance with the load change (compressor inverter and other equipment).

— Consideration of following energy-conservation technologies for a central heat-source system:

Control of the number of heat sources, free cooling systems, large temperature-differential water

supply systems, variable flow control for cooling water pumps, pump capacity control (using an

inverter) and boiler efficiency.

— Consideration of the following energy-conservation technologies for the load side equipment:

Variable blow control for air conditioners, total heat exchangers, air-conditioning systems that

separate the latent and sensible heat, fresh-air intake controls that respond to CO concentration,

and unused energy sources such as underground heat, underground water, and temperature

differences in river water.
4.3.5.3.2 Lighting equipment
— Utilizing high efficiency lighting systems
— Designing and installing solid state lighting systems.
— Designing quality daylighting
— Maximizing daylight availability,
— Providing quality views for all occupants,
— Limiting daylight excessiveness.

— Incorporating lighting controls that adjust to daylight availability, occupancy sensing, lumen

depreciation, and personal dimming.
— Optimizing illuminance

— Designing to ANSI/IES/CIE recommended illuminance levels and visual quality recommendations.

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4.3.5.3.3 Hot water supply equipment:
— Reduction of energy consumption by employing the
...