Sustainability Guide

Why is Saving Energy so Important?

Energy use causes global warming, acid rain and contributes to low-level air pollution in urban areas. There are also concerns about how we will meet an ever-increasing demand for energy.

Under the Kyoto agreement, the UK Government is committed to reducing greenhouse gas emissions to 12.5% below 1990 levels by 2010. It also has a manifesto target to reduce emissions by 20% over the same period, which is supported in the Draft Regional Planning Guidance.

While these targets are important, they will have only a limited impact on reversing global warming. The Royal Commission on Environmental Pollution suggests that a much higher target of a 60% reduction in carbon dioxide (CO²) emissions by 2050 will be required.

Based on current emissions trends, the Intergovernmental Panel on Climate Change predicts that the earth's average surface temperature will rise between 1.4^o and 5.8^o Celsius from 1990 to 2100.

They also predict: more frequent storms sea level rise increased rainfall and greater inflow to estuaries and the sea flooding changes of rainfall pattern during the year - wetter winters and drier summers.

These serious environmental effects have prompted the Government to introduce new environmental legislation. The Climate Change Levy adds 10-15% to the cost of fuel for industrial and commercial users.

The Government's target to achieve 10% of electricity generation from renewable sources will be implemented through the Utilities Bill, which obliges power suppliers to derive a specified proportion of the electricity they supply from renewables.

In addition regional targets for renewable energy generation will be set. A number of renewable energy technologies are viable in the North East. It is estimated that renewable energy developments in the North East Region could achieve between 170 MWe and 600 MWe of generating capacity. In the short to medium term, wind energy, landfill gas, small scale hydro and municipal power, agricultural and forest waste combustion are promising. In the longer term, bio-fuels and photovoltaics are likely to be useful sources of energy.

At the individual development level, Part L of the Building Regulations (relating to the Conservation of Fuel and Power) has been updated. Stringent measures will be needed to improve the energy performance of buildings, including increased U Value and airtightness requirements. Revisions to Planning Policy Guidance notes (e.g. PPG3 on Housing) are also aimed at improving energy performance.

In summary, saving energy will: reduce CO2 emissions and their impact on global warming; reduce SOx and NOx emissions and their contribution to acid rain; reduce the long term depletion of fossil fuel reserves; reduce fuel bills for tenants and occupiers; ensure compliance with current and future; environmental legislation. Buildings are by far the biggest cause of C02 emissions in the UK and hence it is in the development of buildings that the greatest savings can be made.

Buildings 46% Transport 30% Industrial 23% Agriculture 1%

Minimising Energy in Construction and Design

Energy is used in construction in several ways: on building sites, in offices, by machinery and most importantly by transport of materials to and from the site.

Over the course of the construction, the energy wasted can be considerable. The following techniques will keep this to a minimum:

• source materials and labour locally if possible to minimise the distance travelled

minimise the number of journeys by not sending vehicles (e.g. waste skips) out half empty. In addition, an on-site energy-efficiency programme should be installed to ensure that machinery, lights and heating are not used unnecessarily. Energy and fuel use should be metered and monitored and any abnormally high measurements investigated. Targets can be set to achieve continuous improvement in terms of reduced energy use. Staff should be made aware of the need for, and benefits of, energy-efficiency.

• Consider the energy inputs and outputs and their impact on the environment.

Sources of free heat in buildings: Sunlight Occupants (80 watts each) Cooking heat Hot water usage Waste heat from light Waste heat from appliances and machinery

Materials suppliers and manufacturers should be ISO14001 accredited, to ensure that energy issues have been considered in the production of materials. See Design for Minimum Waste, Aim for Lean Construction and Minerals.

A number of techniques can be used to reduce energy demand though building design. Very often these methods will entail no extra capital costs, provided they are decided upon early in the design stage. Energy efficient design is an integrated approach to ventilation, solar gain, daylighting, thermal mass, heating and control systems. It is important to consider these aspects in relation to each other.

The optimum use of energy is to get a balanced system which uses as much free heat gain as possible to minimise heat losses and energy consumption.

Natural Ventilation:
Naturally ventilated buildings consume approximately half as much energy as mechanically-ventilated and air-conditioned buildings. Taking the quoted annual energy running costs for a well-designed energy-efficient, naturally ventilated building as an index of 100, the equivalent for well-designed air-conditioned building is 183, and for a typical air-conditioned building it is 324 (source: ECON 19). The main driving force for natural ventilation during the day is wind creating pressure differences at the roof or on opposing sides of the building.

For natural ventilation to be effective on even the hottest of summer days, building design is critical. Design features which help reduce the cooling load of the building include solar shading, night cooling and providing exposed thermal mass to regulate temperature (e.g. exposed concrete upper-floor soffits). As a very rough rule of thumb, cross ventilation (i.e. ventilation on two sides of the building) can provide around 10 air change per hour (ach). Natural ventilation may not be suitable for industrial buildings where they are used for sensitive processes, or where heat gains are excessive.

Ways to maximise the use of daylight: Daylight Position buildings to avoid obstructions Design the form and layout to maximise daylight penetration Design glazing to maximise daylight in rooms Avoid Glare Use planting and filtering devices Paint interiors light colours, particularly around windows Splay window reveals Introduce light from more than one direction Reflect light off light surfaces Artificial light Use low energy light bulbs (they can save 40% on electricity bills in well insulated houses) Use efficient lighting controls Ensure common areas have natural daylight Use light colours on walls and floors

Passive solar design and natural daylighting:
Building orientation and design that aims to maximise the benefit of solar gain and daylighting is known as Passive Solar Design (PSD). For domestic buildings, passive solar design can contribute as much as 15% of the energy required for heating and lighting.

The main aspects to consider are the orientation and shape of buildings, and the overall site layout, to avoid overshadowing and maximise sunlight penetration. For most commercial buildings however, high internal gains (such as computers, photocopiers etc.) mean that avoiding overheating due to solar gains in summer is a priority.

The main consideration will be providing sufficient daylight while avoiding overheating and the need for air-conditioning in summer.

Artificial lighting is generally the greatest single energy use in non-domestic buildings, being greater than both heating and cooling.

Therefore, designing for daylighting can make a major impact on the energy consumption of the building. Effective PSD will balance solar heat gain in winter for heating, cooling in summer, ventilation, and the provision of daylighting without glare.

Positioning of goods doors:
Goods doors can have a significant contribution to heat losses from industrial buildings. They are often large in size and difficult to close. Goods doors should be well insulated, and where possible a separate personnel door should be provided to avoid unnecessary opening of the goods door.

Minimise heat loss through ventilation: Ensuring doors and windows are draftproof Using timber frame construction for better air tightness - as any gaps in the construction are easy to seal Locate jointing details and seal them Use loose blown fibre rather than rolls or batts Use small heat recovery units where mechanical ventilation is required

Airtightness:
Standard details to ensure airtightness can be found in the BRE design manual for energy efficiency in factories.

Pressure tests may be used following construction to identify and rectify air leakage problems. Under the revised Part L of the Building Regulations, new rules regarding air-tightness are included.

Key points for good insulating practice: Maximise roof, wall and floor insulation Use breathing, natural, low energy products Balance you heating and insulation strategy A little insulation retro-fitted is better than none at all

Structural Insulation Standards:
Insulation of structural elements is required by Building Regulations but higher standards are recommended to reduce energy use and to give long term benefits. BREEAM for Industrial Units gives credit for achieving U Values for roof, floor and walls that are 15% better than building regulations.

Types of Insulation
The most sustainable	Organic - natural (cellulose, flax, hemp, wool, wool fibre, wool wood, cork)
to	Inorganic - mineral (rockwool, fibreglass, perlite, vericulite, foaming glass)
The least sustainable	Fossil Organic - oil derivatives (polystyrene, polyisocyanurate, polyurethane, urea and phenol formaldehyde foam)

Insulation reduces both heat loss in winter and excess solar gains in summer which may cause overheating. Insulation is easy to install in a new structure, trouble free and requires care only to avoid condensation and cold bridges. A thermographic survey (an infra-red scanner to detect infra-red radiation emitted by objects) will allow defective insulation to
be identified.

Sources of Energy with Minimum Environmental Impacts

Renewable energy is any source of energy that replenishes itself and is inexhaustible. Currently most energy for buildings comes from finite and unsustainable fuel sources such as natural gas, coal and nuclear power.

Renewable energy sources should be incorporated into new development wherever possible as it has the following benefits:

Minimises the use of non-renewable resources; Minimises air pollution; Is a 'clean' source of energy; And a 'free' source of energy to the user.

Renewable energy sources should only be used where energy conservation measures have been installed and therefore the amount of water or electricity required is reduced.

Renewable energy techniques can be incorporated in buildings and other projects:

Active Solar Water Heating:
Active solar water heating uses direct and diffuse radiation from the sun to heat water, and can supply up to 50% of the hot water requirements of the average house, and can be used in other applications such as hotels.

A solar collector mounted on the roof collects heat and transfers it via a fluid to the hot water cylinder. Single cylinder systems have a mains back up (electric immersion or heating coil from the boiler). A typical domestic active solar installation costs around £1,500. This gives a payback time of around 10 years where electricity would otherwise be the heat source for hot water, and around 50 years where the fuel would otherwise be gas.

Heat Pump - Ground Source/Water Source:
The term Ground Source Heat Pump (GSHP) generally refers to a number of systems that use the ground, groundwater or surface water as a heat source and / or heat sink. Heat Pumps use electricity to move energy, as heat, from one place to another. In the same way that a conventional refrigerator takes unwanted heat from food and releases it from cooling fins, so the heat pump takes heat from the ground outside and releases it as useful warmth in the building.

The efficiency of the system is described in terms of the coefficient of performance, which is the ratio of the delivered heat energy to the electrical input. Typically GSHPs have a coefficient of performance of around three, which means that for each unit of electrical energy used by the system, three units of usable heat are delivered to the building.

Heat pumps release less carbon dioxide per kWh of heat generated than even an energy efficient boiler.

Photovoltaics (PVs):
Photovoltaic (PV) systems convert solar radiation into electricity. The Direct Current (DC) electricity generated can either be stored in batteries for future use, or converted to Alternating Current (AC) via an inverter for use on-site or export to the electricity grid.

The present high cost of PV means that electricity cannot be generated at an economically viable price. 1m2 of PV cells costs around £800-£1000 and provides around 100-150 kWh per annum in the North East. However, Building Integrated Photovoltaics (BIPV) consist of PV modules which are incorporated into the building structure and replace some of the conventional building materials.

In this way the BIPV provides the exterior façade or roof element in addition to generating electricity, thereby offsetting some or all of the installation cost.

Key Issues for Dwellings Insulate well - aim for 15% better than Building Regulations. 150 mm of loft insulation can cut heating bills by 20%. Double glazing halves the amount of heat lost through windows, and can cut heating bills by 12%. Install understandable heating controls. Consider condensing boilers. Although more expensive that non-condensing boilers, householders can get a grant from the Energy Saving Trust to cover the difference in price - make sure the size if boiler chosen is suited to the amount of energy needed - there are many smaller heating systems available for the low energy dwelling. Encourage low energy lights - although this is ultimately the choice of the occupant, designers should encourage their use. Orientation should allow the house to take advantage of passive solar gains, and south-facing roofs will allow photovoltaics to be retrofitted as and when they are commercially viable. Reduce drafts by ensuring that doors and windows are well fitted, and install draftproofing where appropriate. Install active solar water heating - this uses diffuse and direct sunlight to heat domestic hot water. An installation for a typical house will cost around £1000 and payback times can be as low as 8 years. Reduce the embodied energy of the house by choosing timber frame construction and timber window frames. Where natural gas is not available, ground source heat pumps are preferable to standard electric heating from an environmental point of view. Although rarely used in the UK, they are widely used in Scandinavia and as the UK market grows, prices become more competitive.

Key Issues for Commercial Buildings Consider natural ventilation if at all possible. This can cut energy consumption by half. If certain areas require cooling, consider a mixed mode building, with cooling installed only where required. Maximise daylight - this will have health and well-being benefits for occupants as well as cutting energy consumption. If cooling is required, choose chilled beams or chilled ceilings with displacement ventilation. These systems separate cooling from ventilation so ventilation can be reduced to a minimum. Choose condensing, low NOx boilers. Where it is not possible to have all condensing boilers, ensure that the lead boiler is condensing. Do not oversize boilers. Ensure the lighting levels are appropriate for the building. The British Council for Offices recommends 350-400 lux with a uniformity ratio of 0.8 for open-plan office areas. An appropriate light control system incorporating presence detection, daylight detection and zoning of open plan spaces should be installed. Perimeter areas should be switched separately from core areas. Select appropriate glazing - low emissivity, argon filled double glazing is recommended. Solar control glazing may be necessary for south facing glazing to avoid excessive cooling loads. Shading that can be controlled by occupants should be installed to control solar gains and overheating, as well as glare on VDUs. Minimise embodied energy in construction. Avoid aluminium from non-recycled sources, and install timber for window frames. Seek guidance from the Green Guide Materials Specification. Consider Renewables and Combined Heat and Power (CHP).

Combined Heat and Power (CHP):

Combined Heat and Power (CHP) is a very efficient technology for generating electricity and heat in a single process. Efficiencies of 80-90% are typical. The basic elements of a CHP plant are electrical generators, with the heat generated in the process being utilised via suitable heat recovery equipment for a variety of purposes including industrial processes, community heating and space heating.

CHP can be used in plant of all sizes ranging from 30kW boiler house upgrades (e.g. leisure centres, hotels etc) to 2000MW in industry. Micro-CHP units for individual houses are at the prototype stage.

Small Scale Hydro Power: Hydro power is a mature and proven technology. It involves the generation of electricity using energy from a locally available water source. Modern hydro turbines extract energy from the water in one of two ways depending on the geographical location of the water source. In hilly areas, with a high hydraulic head of water, high-speed impulse turbines are used. In river valleys with a low water head (<20m), 'run of river' schemes divert part of the flow through a low-head turbine.

A well designed hydro electric system should provide a financial payback of 7 to 8 years.

Green Electricity:
Many electricity suppliers currently offer the opportunity to purchase, for a premium, electricity from renewable resources such as wind power, energy crops, hydro power and solar energy. Although the electricity is more expensive, it guarantees the provision of electricity from renewable sources, as well as providing a positive indicator to the energy company that such a demand is required.

Future Energy is an accreditation scheme for green electricity tariffs which is designed to verify the environmental claims made by the electricity suppliers. It is administered by the Energy Saving Trust which is an independent, government-backed organisation. They can supply a list of accredited suppliers, along with the type of tariff offered and the renewable technologies that they invest in.

Electricity suppliers have to produce 10% of their electricity from renewable sources by 2010. The Government is placing a levy of 0.09p/KWh on all electricity consumed to help achieve this. This reinforces the important role renewable energy sources will have in the future.

Wind Power:
Wind power involves the harnessing of the power in the wind to generate electricity.

Wind turbines are available with a range of power outputs from watts to megawatts. Depending on the size (electrical and physical) they can be used in applications from large scale grid-connected systems to small power supplies for individual buildings.

Be Energy Efficient when Using the Building

• Energy efficient plant and appliances can considerably reduce energy use.
• For an industrial or commercial building this is likely to mean plant such as boilers and air conditioning, as well as lighting.
• For domestic buildings it is likely to include domestic appliances as well. Domestic appliances must by law carry the EU-wide Ecolabel, which ranks the overall efficiency of an appliance with regard to water, energy and detergent consumption, or washing performance. The efficiency of a product is given an overall rating between 'A' (most efficient) and 'G' (least efficient). Energy efficient homes generally use 40% less energy than an average home, so can help to combat fuel poverty.

Mixed mode ventilation / efficient use of air conditioning:
In some situations, full natural ventilation of a building will not satisfy the specified internal environmental conditions. This may be due to restrictions on window locations, anxious clients, or predicted internal heat gains greater than 35-40W/m². Where this is the case, savings can be made by opting for a half-way house with suitable areas being naturally or mechanically ventilated, and air-conditioning use restricted to those areas and times when it is necessary.

Variable speed drives:
Heating and chilled water pumps are generally sized for peak heating or cooling demands that only occur for a small proportion of the time. Many existing heating systems, being constant volume, use the same amount of energy for pumping power throughout the year, regardless of the system load, resulting in excessive energy use. Variable speed drives (VSDs) for fans and pumps offer the opportunity for large energy savings, in some cases as much as 60%.

Low Energy Heating, Controls and Zoning:
At outline design stage, more innovative systems such as heat pumps and CHP should be considered where appropriate. Advantage should be taken of the effects of internal and solar gains where possible, with the heating system components sized accordingly.

Over-sizing plant will typically lead to inefficiencies in operation, in addition to higher capital cost. Condensing boilers should be installed to reduce energy consumption for heating. In a multi-boiler system, at least the lead boiler should be condensing. The condensing boiler will require a condensate drain and the flue should be sited where the plume will not cause inconvenience.

Industrial and commercial buildings should be zoned by floor and ideally by orientation, to allow a single floor to be heated out of hours rather than heating the whole building. If cooling is provided, care should be taken to provide controls that prevent simultaneous heating and cooling of the same zone.

A 7-day programmer should be provided ideally providing optimum start with weather compensation. Optimum start control allows the heating and cooling systems to switch on at a suitable time (depending on external temperatures) to ensure comfortable temperatures when people arrive in the building. Weather compensation adjusts the amount of heating provided to take account of external temperatures. Thermostatic Radiator Valves (TRVs) should be fitted to radiators to allow them to be individually controlled.

Domestic Hot Water Options:
Supplying the hot water load with a calorifier served by the main boilers can be extremely inefficient as the main boiler must be fired in summer, to meet a very small load.

Where the summertime demand of DHW is low, local point-of-use water heaters should be used. This system also reduces the need for maintenance associated with avoiding the risk of Legionnaires' Disease. Active solar water heating should be considered for all types of buildings at the early design stage.

Artificial Lighting, Controls and Zoning:

Artificial lighting should be designed to complement daylighting and be controlled to provide additional lighting only where and when it is needed. Compact fluorescent lights should be encouraged in all types of buildings. High-frequency ballasts are recommended for luminaries as they use less energy and avoid the flicker from traditional fluorescent lighting, which can cause headaches to occupants. In commercial buildings lighting circuits should be designed and zoned to allow control systems to turn off lights automatically when areas are unoccupied and where daylighting is sufficient. In houses, dimmer switches should be installed in convenient locations.

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Rules of Thumb

• Minimise Energy in Construction Use

Sources of Info

• Site Layout Planning for Daylight
• Natural Ventilation in non-domestic buildings, Applications Manual
• Refurbishment Of Air-Conditioned Buildings For Natural Ventilation, Technical Note
• Energy Consumption Guide 18 - Energy Efficiency in Industrial Buildings and Sites
• Energy Consumption Guide 19 - Energy use in offices
• Good Practice Guide 34 - Energy efficient options for new offices for the design team
• CIBSE Code for Interior Lighting, The Chartered Institute of Building Service Engineers (CIBSE)
• Best Practice in the Specification for Offices, British Council for Offices
• Environmentally Friendly Systems and Products: Heating Systems, BSRIA Report
• Solar Thermal Systems in Europe - Information Booklet
• Directory of Energy Efficient Housing
• Photovoltaics and Architecture
• GPG303 The Designers Guide to Energy Efficient Buildings for Industry
• Good Practice Guide 287, The Design Team’s Guide to Environmentally Smart Buildings
• Good Practice Guide 234 - Guide to community heating and CHP, Commercial, public and domestic applications
• Combined Heat and Power Association
• Ground Source Heat Pumps - A Technology Review
• Photovoltaics in Buildings - A Design Guide
• Photovoltaics in Buildings - Testing, Commissioning and Monitoring Guide
• The British Photovoltaic Association
• British Wind Energy Association (BWEA)
• The Centre for Alternative Technology
• BREEAM 5/93 for New Industrial Units
• BREEAM 98 for Offices
• ETSU (for industrial issues)
• BRECSU (for buildings issues)

Case Studies

• Cassop Primary School
• Solar Office, Doxford International Business Park