Farm buildings of all kinds may present significant energy-saving opportunities.
For intensive producers, heating, cooling, ventilation, lighting and mechanical equipment operating within buildings accounts for the majority of on-farm energy use. In these sectors, the energy consumed in such facilities may represent as much as 30 percent of input costs (NSW Farmers, 2013).
In the broadacre sectors, the energy used in and by farm buildings is likely to be only a small proportion of the total energy consumed. Nonetheless, valuable savings may be achieved at relatively low cost.
Energy efficiency in farm buildings is a broad topic, involving many different kinds of opportunities and solutions. This paper aims to provide a general overview and is intended to be read in conjunction with the supplementary papers listed in the Further Information section. Also keep an eye out for the case studies we will be developing under the Farm Energy Innovation Program throughout 2014.
While energy savings may be achievable in every farm building, these savings may not compensate for the effort and/or cost involved.
As a first step, we recommend that all farmers conduct at least a ‘level one’ energy audit for their properties.
A level one audit will identify major energy savings opportunities and provide the basic numbers necessary to estimate payback periods for specific solutions.
Farmers managing intensive facilities – for example dairy, pork, poultry, horticulture and aquaculture – may benefit from a level two audit, which provides the detail required to solve relatively complex energy-efficiency problems.
General farm buildings
A majority of Australian farm houses are well insulated and relatively energy-efficient. Nonetheless, we recommend that you review your home for potential energy savings. There are excellent resources available to assist with domestic energy efficiency (see Further Information).
Typically, other farm utility buildings, such as machinery sheds and outhouses, are not well sealed or well insulated. While this is practical in most instances, it may be worth improving the energy efficiency of certain utility buildings. Workshops that you need to heat in winter, for example, might be using more energy than you realise.
Checklist: Quick wins
- Examine shed lighting. Identify your lighting requirements and consider alternative, energy-efficient lighting options.
- Lighting and equipment sensors. Ensure that lights and equipment are running only when necessary to minimise the use of electricity and fuel.
- Seal up leaky buildings. Use materials such as foam to seal off leaks in walls and ceilings in farm buildings; install door and window weather stripping; and ensure all building operators/users understand the correct procedures for opening and closing shed access points.
- Introduce mechanical ventilation to climate-controlled farm buildings. With mechanical ventilation, you can control the amount of ventilation and air exchange within climate-controlled buildings and sheds, minimising heating and cooling losses.
- Check insulation of hot-water and heating pipes. Typically, pipes that transport hot water are made of metal, PVC or other highly conductive materials. A quick review may turn up missing or failing insulation.
- Perform routine maintenance. Routinely clean air filters, motors, fans, belts and other mechanical equipment housed in buildings and sheds to keep them operating at peak efficiency.
- Consider using light/reflective roofing materials. When replacing, finishing or painting the roofs of sheds in which cooling or ventilation is required, choose light-hued, reflective paints or materials.
Facility climate control
Intensive production facilities, such as greenhouses, animal production sheds and cold storages, require consistent and precise temperature control. The building shell, passive ventilation, lighting, heaters, and the motors driving HVAC and refrigeration systems all contribute to the total energy efficiency of the system.
Often, older farm buildings and sheds were built with little thought of energy use and efficiency. Air-conditioned buildings with uninsulated roofs offer an excellent opportunity for energy savings via a variety of insulation materials and installation methods. Retrofitting insulation can present complex choices, however. It is advisable to obtain and compare quotes and ideally, to seek independent advice.
Farms buildings with cooling systems and ventilation fans can benefit from light-coloured, reflective roofs. Roofs typically absorb UV radiation from the sun, heating up the contents of the building. Covering an existing dark-coloured roof or installing a new light-coloured, reflective roof can significantly reduce the amount of solar radiation absorbed and lower surface temperatures on the roof as well as temperatures inside the building it covers.
Air leakage and building tightness
Controlling air exchange and preventing leakage of conditioned air is essential. Sealing a leaky building can be a simple matter of applying foam sealants to gaps and cracks, weather-stripping and/or adding plastic air barriers. Reviewing your buildings for obvious gaps can reveal some easy savings. Controlling air exchange also involves ensuring that staff implement correct procedures around the opening and closing of doors and windows.
Ensuring that equipment is maintained properly is vital to getting the most out of your assets. Motors, fans, compressed-air hoses and pumps all have to be serviced regularly to ensure they are operating within expected guidelines.
Equipment replacement and upgrades
Full or partial early retirement of existing equipment provides you with opportunities to incorporate new technologies such as variable speed drives or condensing equipment that runs far more efficiently. Day-to-day efficiency gains may provide enough savings to make these types of upgrades and replacements cost-effective within a short period of time.
Assessing the light fixtures in farm buildings and upgrading those that are old and outdated can lead to major savings. New developments in lighting technology can reduce energy usage by more than 90 percent. Much like early retirement of other types of equipment, replacing outdated lighting technology can provide significant savings from day one.
Simple bulb switching may not always be applicable, due to the differential voltage requirements in existing lighting fixtures. Farmers can take advantage of the NSW Energy Savings Scheme by selecting an accredited certificate provider from the NSW ESS website (NSW Government Energy Savings Scheme, 2014). These providers can offer expertise and lower prices while helping you switch to high-efficiency equipment.
Smart sensors and automation
There is wide range of smart technology available to automate the operation of lighting and HVAC systems so as to optimise energy use.
Lighting sensors are a common solution for reducing electricity demand from lighting. Lighting motion sensors ensure that areas receive adequate lighting when necessary, without wasting energy lighting unoccupied areas.
Air quality and temperature sensors can be used to continuously optimise the operation of fans and HVAC systems. While automation can be expensive, benefits may include energy savings, improved growing conditions (by removing operator error) and a reduction in labour costs.
Power quality problems can be a significant hidden cost for farmers. Installing line conditioners and voltage optimisation devices can reduce electricity costs and extend the life of expensive electrical and electronic equipment.
Renewable energy generation on farm should be considered as part of a total energy solution, helping to reduce your operation’s reliance on external energy sources.
Solar photovoltaic systems are a proven technology and can be cost-effective for many operations.
Likewise, solar hot water is a robust and effective technology in many applications.
The conversion of waste to energy is an area with great potential for some production systems. For example, capturing methane from animal manure to drive electricity generators can be cost-effective for large piggeries and dairies.
Those running farms in windy locations may want to consider the viability of installing farm-scale wind turbines.
If you are constructing a new facility there are many opportunities to incorporate energy efficiency into its orientation, structure and materials. Each intensive sector has specific requirements for shed functionality. Established, conventional designs are not necessarily ideal, however, and there is significant scope to improve the energy efficiency of most production sheds. NSW Farmers is working with various sectors including poultry and horticulture to explore innovation in this area, and will be publishing outcomes as they become available. In addition to exploring the information sources listed below, we recommend that you conduct your own research and link up with other innovative farmers, designers and builders in your sector and region.
As noted above, an energy audit of your existing facility is a logical first step; it will clarify areas of inefficiency, allowing you to prioritise those areas in which savings can be made.
Checklist for new facilities
- Building orientation. Is there scope to locate and orient the building so as to optimise passive heating and cooling (solar orientation, breezes, shading)? Does Council provide incentives in this regard as part of the Development Approval process?
- Structural materials. Have you compared the costs and benefits of alternative materials for roofing, walls, floors and structural elements? Some structural materials have better thermal properties than others.
- Insulation and sealing. Have you optimised investment in quality insulation and sealing? A higher upfront cost may be justified by energy savings in longer term.
- Renewables. Have you considered options for meeting some of your energy demand from renewable sources?
- Can improving your energy efficiency benefit production efficiency? For example, a concrete floor could help stabilise temperatures as well as assisting with cleaning and/or biosecurity.
Obtain independent advice
Before committing to changes and investing capital it is essential that you obtain expert and independent technical advice on the solutions you are considering. In this regard, it is preferable to hire a consultant who is not a vendor of specific equipment and whose focus is on identifying the best suite of technologies for your particular business.
Farm Energy Innovation papers
- Energy-efficient farm lighting - There are a variety of lighting technologies available. This information sheet explores agricultural applications and efficiencies available in lighting in the current marketplace.
- Efficient ventilation technologies - Fan maintenance, efficient motor technologies, fan types and criteria for evaluating fan technologies in agriculture.
- Heating technologies in poultry sheds - Consider the pros, cons and differences between radiant and air-heater technologies in poultry sheds.
- Energy-efficient HVAC in the mushroom industry - Smart equipment design and efficient HVAC technologies can be used to make energy savings in the mushroom industry.
- Poultry-shed versus ventilation: passive to mechanical - Implementing mechanical ventilation in poultry sheds can help you achieve optimal transfer of temperature and maximise the removal of harmful gasses from production facilities.
- Reflective roof coatings - As reflective roof coatings reflect heat from the sun rather than absorbing it, such coatings can reduce cooling loads on buildings.
- Insulating farm buildings - Reduce heating and cooling loads in buildings by adding insulation and increasing existing R-values, making roofs and ceilings top priorities.
- Compressed air systems: air-leak reduction - Leakage accounts for nearly one third of compressed air energy consumption. Institute a proactive leak repair and maintenance program to reduce energy loss through leakage.
- Compressed air: minimise pressure drop - Minimise pressure drop in compressed air systems to meet end-use demands and overcome friction and gravitational flow losses (pressure drop) in the pipe/hose network.
- Heat recovery in grain dryers - Utilise heat recovery to reduce energy needs in grain drying.
- Solar hot water - Understand how solar hot water works and where this technology can be useful in agriculture.
- Heat pumps - Gain efficiency by using ground-sourced or air-sourced heat pumps to assist in water heating and space climate control.
- High-efficiency motors - Consider the savings you could make through implementing high-efficiency motors in farm facility equipment.
- Variable speed drives in agriculture - Replacing existing fan motors with variable speed drives means that motors can be run at a range of speeds to maximise their efficiency.
- Power factor correction - On large farming operations, power factor can directly influence electricity charges. Correcting this can reduce your energy bills.
- Voltage optimisation - Remote farming operations are subject to voltage variance, which can negatively affect mechanical equipment. Voltage optimisation is also a potential energy-saving measure
- Refrigeration summary - A summary outlining energy-saving opportunities related to refrigeration, including insulation, variable temperatures and head pressure, and factors to consider when upgrading or replacing equipment.