Services

8.2Low or zero carbon technologies

This chapter gives guidance on meeting the Technical Requirements for low or zero carbon (LZC) technologies.

Introduction

This chapter provides guidance on low or zero carbon (LZC) technologies acceptable to NHBC. Other systems that follow the general principles of this chapter may also be acceptable, subject to specific agreement with NHBC.
Additional requirements for solid fuel and oil fired boilers are given in Chapter 6.8 ‘Fireplaces, chimneys and flues’. Guidance on other internal services is given in Chapter 8.1 ‘Internal services’.

This chapter provides guidance on the following technologies:

Biomass boiler - Systems which burn wood pellets or chips for space and/or water heating.

Heat pump - Systems which transfer heat from low energy sources. The most common sources are ground, outdoor air and exhaust air.

Solar photovoltaics (PV) - Systems which convert solar radiation into electricity.

Solar thermal water heating - Systems which convert solar radiation energy to space and/or water heating.

Wind turbine - Systems which convert wind energy into electricity.

The illustrations provided within the introduction are generic and do not indicate the only possible systems acceptable to NHBC.

Definitions for this chapter

Controls	Controls are used to operate and/or regulate the system and may be electrical or mechanical.
Exclusion zone	An area where entry is restricted during periods when maintenance is in progress, to prevent risk of injury or loss of life.
Ground collectors	The component of a ground source heat pump system which absorbs heat from the ground. Collectors can be installed either horizontally or vertically in the ground. They may also be incorporated into proprietary foundation systems.
Interstitial condensation	Condensation occurring within, or between, the layers of the building envelope.
Inverter	A device that converts direct current into alternating current.
Islanding (island mode operation)	Where an LZC technology feeds the network or local distribution system during a planned or unscheduled loss of mains supply.
Low or zero carbon (LZC) technologies	A term applied to renewable sources of energy, and also to technologies which are significantly more efficient than traditional solutions, or which emit less carbon in providing heating, cooling or power.
Open loop system stem	A heat pump system that extracts water from an underground source, pumps it through a heat exchanger and returns it underground.
Parallel electrical generation	A system in which building loads can be fed simultaneously from the national grid or electricity supply grid and on-site sources such as wind turbines and photovoltaic panels.
Performance	The manner or quality of functioning for a material, product or system.
Refrigerant pipework	Carries refrigerant between the indoor and outdoor unit of a split system. Normally made of copper and must be insulated and protected from damage.
Renewable energy	Energy from naturally available sources that can be replenished, including energy from the sun, the wind and tides, and from replaceable matter such as wood or other plant material.
Split system	A type of heat pump in which the condenser is located indoors, the evaporator is located outdoors, and the two are linked by refrigerant pipework.
Switchgear	The combination of electrical switches, fuses and/or circuit breakers used to isolate electrical equipment.