Clean & Clever Energy Toolkits Hot Water System

Transcription

1 Clean & Clever Energy Toolkits Hot Water System

2 Acknowledgement This Activity received funding from the Department of Industry as part of the Energy Efficiency Information Grants Program. Disclaimer The views expressed herein are not necessarily the views of the Commonwealth of Australia, and the Commonwealth does not accept responsibility for any information or advice contained herein. BIEDO Burnett Inland Economic Development Organisation 10 Moore Street, (PO Box 94), Goomeri, Qld 4601 Phone: (07) Website: BIEDO Clean and Clever Facebook Page: 2

3 How to use this fact sheet Hot Water System This fact sheet forms part of the Clean and Clever toolkits, to assist you to reduce your business energy use. Please read this fact sheet in conjunction with the Energy Information Toolkit and the Planning, Implementing and Monitoring Toolkit. Additional fact sheets that may assist you: Laundry These can be found at Hot Water System Many businesses use a hot water system for one purpose or another, such as for cleaning, showers, or washing clothes. There are many different types of hot water systems available and they come in a range of shapes and sizes to suit different purposes. The most common hot water systems (HWS) in this region include: Electric storage HWS Instantaneous (gas) HWS Solar HWS Heat pumps Think about: How often do you use hot water and what is it used for? All day, every day for cleaning, showering, etc. or just for washing a few mugs and plates at the end of the day? Small businesses, such as main street retailers, often have a storage hot water system operating continuously. Consider if you can operate without it or if there is a more suitable alternative, such as boiling the kettle for washing dishes or an instantaneous hot water system or tap. 3

4 Electric storage HWS Electric storage systems are the most typical HWS that is found in the Wide Bay Burnett Region. They are a conventional system that uses electricity to heat the water that is stored in a cylindrical storage tank. Advantages: Cheaper purchase and installation cost than most systems Can run on an off-peak tariff designed for electric hot water systems Disadvantages: Expensive running cost as solely relies on electricity (even with off-peak tariff) Contributes the most greenhouse gas emissions of all of the hot water systems available Takes up space Instantaneous water heaters This type of system only heats as much water as you need, when you need it. If you turn on the tap, cold water flows through a heat exchanger, igniting a gas burner or electric element. Advantages: As long as there is gas or electricity, you'll never run out of hot water Gas systems are generally cheaper to operate Gas systems create less greenhouse gas emissions that electric system Disadvantages: In areas, such as rural Queensland, where there is no centralised gas network and gas cylinders are used, there is a greater likelihood of running out of gas. Careful planning is required regarding the purpose and volume of hot water needed and how often you will need to refill the gas. NB.: Gas can be more expensive in the inland towns due to transportation costs. Research the cost of refilling gas in this region when considering using a gas hot water system. 4

5 Solar Hot Water Solar Water Heater systems work efficiently if they have good access to sunlight throughout the day to maximise the amount of energy collected. This is achieved through a variety of processes depending on the type of system used. In most systems, any additional energy needed to heat water to a higher temperature, i.e. on overcast days, is provided by either a gas or electric booster. Another reason for boosting is to ensure the water is safe. When water is stored it needs to be heated to at least 60 C as a precaution against the development of legionnaire s disease in stagnant parts of the water tank. Although this is rare in hot water systems, it can occur if the water is kept at less than 50 C. The booster raises the water temperature to above 60 C regularly. Advantages: Combined with a gas booster, this system has the lowest ongoing cost Least amount of greenhouse gas emissions Disadvantages: Generally roof mounted may not be suitable for all roofs Is generally the most expensive system to purchase and install Overcast weather can reduce efficiency and a booster may be required 5

6 Heat Pumps Heat pumps use the refrigeration cycle. Heat from the ambient air is absorbed by a refrigerant via a heat exchanger. The refrigerant then travels to the hot water tank, and the heat is transferred to the water via another heat exchanger. The cooled refrigerant then returns to be heated again. Advantages: Require much less electricity than a conventional electric water heater. An electric water heater will convert 1 kw of electricity into 1 kw of heat energy, whereas a heat pump, which only requires electricity to operate the compressor, under optimal conditions can convert 1 kw into 3 4 kw of heat energy. Ground mounted, avoiding concerns about aesthetics on roofs or excessive weight on roofs. Split system option enables the heat pump to be located in an optimal location for performance and aesthetics. Will work in most conditions for example, in cloudy conditions and at night although they are more efficient in hot and humid conditions. Therefore, heat pumps can be a good option if solar hot water is not appropriate and the climatic conditions are suitable. Commonly have frost-protection measures (like SWHs) to prevent damage due to freezing at low temperatures. Disadvantages: Not suitable for cold climates. Less efficient in in-land areas where the temperature drops considerably during winter or where frosts occur. When frost-protection methods are active, the boosting element will be required to meet all of the hot water demands. Generally more expensive than conventional water heaters. Can be noisy (similar to an air conditioner). Placement of the system needs to be carefully considered, and the noise of the heat pump running at night may breach noise restrictions or cause noise issues for neighbours. 6

7 Improving practices Reduce your thermostat temperature of your storage hot water system to o C or your instantaneous hot water system to 50 o C. This will reduce over-heating and associated electricity costs. Remember not to reduce the temperature to less than this as harmful bacteria can thrive in lower temperatures in stagnant water in your system. Insulate pipes to minimise heat loss Use water-saving showerheads, flow restrictors and aerators. The less hot water you use, the less it costs to heat. Check for water leaks and have them repaired immediately. Other systems to consider On-wall instant boiling water Instant boiling-water taps On-wall instant boiling water These systems may be placed in the staff room and/or kitchen to reduce the electricity use associated with boiled water. If people in your business are accustomed to several cups of hot beverage throughout the day, this may be a more energy efficient alternative to an electric kettle. An on-wall instant boiling water system has a small storage capacity for boiling hot water. Systems vary as to the amount of electricity they use. For example, a small system that produces boiling hot water for 9 cups at a time uses 1.5kW. Alternatively, an electric kettle may use 2kW or more to operate. 7

8 Instant boiling-water taps These systems provide instant boiling water similar to an instantaneous hot water system. They are generally placed under the sink (or nearby) with a separate tap provided on the bench, next to the sink. These systems are considered more energy efficient than electric kettles. Most models come with a stand-by mode which uses considerably less energy when not actively boiling water. Comparison example On-wall instant 1.5kW x $0.26/kWh = $0.39 per hour Electric kettle 2.4kW x $0.26/kWh= $0.62 per hour Please note that these estimates vary considerably depending on your appliance, volume and use. Please you these estimates as a guide only. 8