Solar Technology

The energy generated as a result of converting sunlight into usable forms of renewable energy. Systems typically convert solar energy into electricity or thermal energy forms and can come in many formats. The energy generated if used in the building, reduces the overall energy demand of the building. Rooftop systems are the most common for generation buildings and therefore the ratio of available roof area to internal usable space is important in deciding whether the building can offset all of its energy consumption without some form of offsite measure.

Space Heating

The amount of active heating required to maintain a desired temperature for a conditioned space. The energy required is dependent upon gains and losses in the space. This energy demand is dependent on several building factors, including:

• Thermal performance of the building fabric
• Air tightness of building envelope
• Ventilation type and performance
• Thermal mass of internal environment
• Internal gains from people, equipment, lighting, cooking etc.
• Solar gains through glazing

Domestic Hot Water

The energy required to heat and maintain water at the temperature required for domestic hot water, typically 55° – 60°C in the UK. Hot water demand is predominantly influenced by the building users but can also be impacted by the quality of storage, pipework and flow rate of fixtures.

Space Cooling

The amount of active cooling required to maintain a desired temperature for a conditioned space. The energy required is dependent upon gains and losses in the space. This energy demand is dependent on several building factors:

• Thermal performance of the building fabric
• Air tightness of building envelope
• Ventilation type and performance
• Thermal mass of internal environment
• Internal gains from people, equipment, lighting, cooking etc.
• Solar gains through glazing

Fixed Lighting

The energy required to supply artificial light through permanent fixtures and fittings. The energy demand is dependent on:

• The level of natural daylight allowed into the building
• Efficiency of lighting fixtures
• Controls and zoning

Appliances, Cooking & Plug Load

The energy demands associated with plug-in appliances and cooking. These demands are difficult to predict as the use is dependent upon occupant behaviour. Although difficult to reduce, there are ways to influence these demands through building design.

Refrigeration

The energy demand required to provide cooling to refrigeration equipment, not for the purpose of space cooling. In a retail environment this energy is mainly used for coolers, chillers and freezers, and can represent around 50% of a supermarket’s energy costs. However, refrigeration is found elsewhere, such as datacentres where it used to extract heat from IT infrastructure.

IT Equipment

The energy demand required to power IT equipment. The scale of IT equipment can differ considerably depending on the needs of business and individuals but the equipment in offices can account for around 15% of the energy use of the building.

Specialist Mechanical Ventilation

Some areas of a building may require specialist ventilation systems to deal with issues such as pollutant, fumes, smoke, overheating etc. Examples of this are enclosed car parking areas, commercial kitchens and building corridors. This building energy use can be difficult to predict due to its intermittent nature and its dependency on building usage.

Vertical Transportation

The use of lifts is an often-unmeasured energy use in buildings, for commercial buildings however vertical transportation can account for around 5-8% of the building energy use, with the standby consumption using a considerable amount of the energy. Other impacts on the energy consumption of lifts are control systems, motor types, sizing and accuracy of traffic data.