Solar Water Heating Systems
Contents
1. What are the available system sizes The easiest way to determine the optimum size for a solar water heater is to match the size to the number of occupants in the home and their water use As well consider planning for the needs of future occupants The average hot water usage for your house will also depend on the number of appliances requiring substantial amounts of hot water such as dishwashers washing machines whirlpools or hot tubs A solar water heater usually comes in three standard sizes and corresponds to your daily hot water use 150 L day 225 L day and 300 L day See Table of Yearly Energy Requirement for Water Heating on page 15 to determine the system size you will need These sizes vary according to the volumes of hot water the heaters are designed to deliver on an average day and are not a rating of their maximum output Where should the solar water heater be installed Your solar water heater dealer will have the expertise to provide you with proper site and installation recommendations However before making your final decision look at your options Take into account the appearance of the col lectors in each possible location Ideally the mounting location should remain unshaded for at least 80 percent of the time between 9 00 a m and 3 00 p m during the winter and summer For seasonal units only the sum mer period is critical Shading can come from your own house from trees or shru2. hot water in your home However most small systems for example systems with 3 m of collectors do not come with a storage tank The best location for the collec tors ison an unshaded south facing roof or wall For excellent performance solar collectors should face due south and be set at an angle of 18 50 from the horizontal plane Collectors can also be mounted on a sturdy frame near your home or can be integrated into the roof of a storage shed The solar collectors typically require a flat mounting area of about 3 m for each collector Most installations require one to two solar collectors A small path is required for the piping which connects the solar collectors to the storage unit The piping usually can be installed through closets cold air returns wall cavities and along the outside wall of the home What will a solar water heater do to the appearance of our house Components for solar water heaters are located outside and inside your home Properly installed solar water heaters will not detract from your home s appearance or disrupt your normal household routines Taking asmall amount of time to examine the different possible locations for the solar collector array can make a large difference on the visual appeal of the final installation On the outside of your home the largest visible component is the solar collector array Solar collec tors look similar to low profile s
3. cause they can operate in all climate conditions Because these solar water heaters operate all year they normally provide more solar hot water than a seasonal water heater These products require maintenance comparable to conventional water heaters Maintenance will ensure good performance and increase your energy savings A Thermosiphon solar water heater at Camp Queen Elizabeth Beausoleil Island on Georgian Bay Ontario Courtesy of Solcan Ltd Seasonal solar water heaters If your family does not use the residence during the wintertime you should consider buying a seasonal solar water heater Seasonal solar water heaters are ideal for summer vacation homes and for warmer regions not requiring freeze protection Ideally they are designed for use only during the spring summer and fall For cottage use a seasonal unit with a safe low temperature rating of 5 C or 0 C is usually adequate For residential use a sea sonal unit with a safe low temper ature rating of 0 C or 10 C should be chosen In some West Coast communities a 10 C seasonal solar water heater can be used all year but in most parts of the country it can only be used for about eight months of the year Good examples of seasonal solar heaters are batch heaters or inte gral collector storage systems Seasonal solar water heaters must be shut down and drained when the temperature drops below the water heater s safe low temperature rating
4. have hot water 0 ccc ccc eee eee ce eee teeter esse 4 Is our house suitable for a solar water heater ccc cece eee cee ee eee ee eee eee 4 What will a solar water heater do to the appearance of our house 020 cece eeeeee 5 What type of solar water heater should we buy cece cece cece cece cer eeevcee 6 What do we need to know before we contact a dealer 2 cece cere reer eres 6 Do we need a year round or a seasonal solar water heater LL eens 6 What are the available system sizes LL 4 tenets 7 Where should the solar water heater be installed ete 7 How do we select dealer coseisverso idonis sissooiertmaos Ao Di Sa SOE Rae 10 Where do we find adedler 2 cctcicdvntuxe kev ered 555940455 0009 0S TATT See PEER RES 10 What should be expected of the installer 0 0 ccc eee 10 What do we need to know to complete our own installation 0 ccc ua 11 What maintenance should we do cc cece ce eee ee eee ee eee ee ee eee treet eens 11 How can we further increase the energy savings ccc eee reer cece eee mana nena 11 What other ways can solar energy improve the quality of the energy we use 12 How does a solar water heater work 2 cece cece eee eee eee ee eee treet eens 13 Energy Collection ci 3 408 set a SEP wee ee BEE EE EE EE ELE Sere 13 Energy TANS
5. heats approximately one third of all residential pools Passive solar heating incor porates the use of solar energy into the architectural design and selection of building materials such as windows to maximize the benefits of solar radiation Active solar heating can also be used to heat floors or the space of buildings Applications include radiant floor heating and solar air heating systems such as the Solarwall which preheats venti lation air to reduce heating costs and improve air circulation Photovoltaic systems convert the sun s energy into useable electricity These systems are now being used to supply the electrical needs of residences that are separated from the electrical grid Some homeowners also use photovoltaic modules to reduce dependence on utilities within grid serviced areas 12 a a A Unglazed solar collectors are commonly used to heat residential pools Courtesy of Taylor Munro Energy Systems Inc HOW does a solar water heater work Solar water heaters perform three basic operations before the hot water comes out of your tap 1 Energy Collection Sunlight is collected and converted to heat energy The solar collector is mounted on or near your home facing south As the sunlight passes through the collector s glazing it strikes an absorbing material This mate rial converts the sunlight into fe heat and the glazing prevents the heat from escaping in a similar ma
6. ic rd adie oe bb bibs MACROSS Pa SEK DI SS SS SATS ROR 14 ENG OY Orage vona she tinal natatlaahoa aes ons ps eo de kad bee a Arnesen ee PEMD 14 Determining your energy savings ua u e ua cece eee eee ee reenter seer eee 15 Table of yearly energy requirement for water heating u e eee 15 Calling your SAVINGS aaret CURR Osh de wees ene waste ES 16 Glossary 6 25 Gaia EE ite ES rap ce AS seh tle de Se ee ets et SR ellen ES 17 Where can we find out more about solar energy 0 cc cece eer c eee eee ere eeeens 18 Reader Survey 050151505308 see karsedake eee e head os dema os sa dE Oder Od Boe se dies 19 y About this Guide This Guide has been prepared to assist consumers with the purchase of a solar water heater also known as a Solar Domestic Hot Water SDHW system for their home Some of the topics covered in the Guide include benefits of solar water heating how a solar water heater works selection of a product and dealer installation and operation of a system and product and dealer selection The Guide is not a how to manual on installing a solar water heater Benefits of a solar water heater What are the benefits of a solar water heater Solar water heaters provide you with several benefits over conventional water heaters You will reduce your hot water heating costs You will also be directly reducing greenhouse gas emissions carbon dioxide CO released into t
7. sensors and adjust the water heater You should dis cuss the warranty limitations for do it yourself installations with your dealer You are also responsi ble for meeting local building regulations and electrical and plumbing codes What mainte nance should we do Routine checks and maintenance will ensure your savings are consistent Once your solar water heater is producing hot water a monthly check up is recommended There are three easy ways to verify that your system is running well 1 Look to see that the pump is operating when it is sunny 2 Check carefully that the pipes are warm 3 Review your energy bills to confirm your savings To ensure the water heater is collecting solar energy when the checks are made complete the checks on a sunny day just after you use some hot water Be care ful the pipes can be very hot Maintenance of a solar water heater should be carried out according to the manufacturer s recommendations Your solar water heater is an appliance It should be maintained on a regular basis like your other heat ing and cooling systems If you have an antifreeze system the antifreeze should also be checked every 1 to 2 years according to the manufacturer s recommenda tions As well if you carry out your own maintenance ensure that the manufacturer s mainte nance practices are followed and that you use only recommended antifreeze for topping up or replacement You sh
8. you in selecting the best model for your needs and help select a suitable location for the system In most cases dealers can also offer complete installation ser vices Before contacting a dealer however you should become familiar with the various types of solar water heaters and their suitability for your needs A variety of solar water heater designs are available for con sumers There are variations in collector styles and component arrangements as well as different methods of freeze and over heating protection If you are planning to use a solar water heater year round in Canada it mus be protected from freezing in the winter and overheating in the summer Solar water heaters that meet the Canadian Sandards Association CSA International guidelines have automatic controls to prevent overcharging the solar heater i e to prevent potential scalding water temperatures The following are common system types the first two can be freeze protected in the Canadian climate e Antifreeze systems use special fluid to transfer heat from the collector to a heat exchanger in the storage unit These systems are fully freeze protected prevent contamina tion of the hot water and can operate in all climate condi tions Snow will slide off the collector as the sun begins to warm them On days with heavy snowfall performance can be increased by removing the snow off the collectors Drainback systems auto m
9. Solar VVaterHeing Systems A Buyers Guide ll pef bd ge naturelles Canada This digital mosaic of Canada produced by Natural Resources Canada Canada Centre for Remote Sensing is a composite of individual satellite images The differences in the density of vegetation are illustrated through shading Solar Water Heating Systems A Buyer s Guide Prepared for Natural Resources Canada with the assistance of Michael Noble EnerWorks London Ontario Layout and design by Mantle amp Overall Communications Ottawa Ontario This guide is distributed for informational purposes only and does not necessarily reflect the views of the Government of Canada nor consti tute an endorsement of any commercial product or person Neither Canada nor its ministers officers employees or agents makes any warranty in respect of this guide or assumes any liability arising out of this guide Recycled paper Her Majesty the Queen in Right of Canada 2003 Cat No M92 179 2000E ISBN 0 662 28486 0 Aussi disponible en francais sous le titre de Les chauffe eau solaires Guide de l acheteur pIN pr 3 3 Ss 3 ME ay Table of Contents About this Guide cou cera ds RENEE os Re EE a EE SEEDEDE ah a EE Suk 2 What are the benefits of a solar water heater 0 cece eee ee ee eee ee eee renee 3 What is in a solar water heating system 4 44 cece cece eter eee eee eee e eee e nee 4 Will we always
10. at the solar water heater has been properly installed and that you fully understand how the appliance works e The installer has provided a signed checklist verifying that the installation has been checked for plumbing leaks that roof and wall pipe pene trations are properly sealed and that outside pipe insula tion is properly jacketed and sealed against the weather e You have an owner s manual You should understand how to shut down isolate and drain the water heater in an emergency how to check that the water heater is operating properly e how to drain a seasonal water heater in the fall and refill it before starting it up in the spring e how to carry out any routine maintenance such as topping up fluid reservoirs e when to call a qualified solar technician to check or replace antifreeze and e details of any warranty covering the installation Completing your own installation What do we need to know to complete our own installation The cost of installing a solar water heater can be reduced if consumers carry out some of the work themselves Installing a solar water heater that will deliver reliable performance consistent with the performance rating requires some experience in elec trical plumbing and carpentry It is important to complete the installation to CSA standards Some specialized knowledge is required to mount solar collec tors prime the collector piping install control
11. atically drain the collectors when they are not collecting solar energy or when the temperature of circulating water is 3 C or less Make sure that the system s minimum temperature rating is appro priate for your climate e Thermosiphon systems do not have freeze protection and are popular for cottages where water heating is needed only in the summer These solar water heaters are often less expensive than models incorporating freeze protection What do we need to know before we contact a dealer Before meeting with your dealer you should review the following questions Do we need a year round or a seasonal solar water heater This depends on when you will be using the residence where the solar heater is installed Year round solar water heaters can withstand the extremely cold temperatures often experienced in Canada These types are recommended if the residence is used throughout the year and isin aclimate requiring freeze protection Seasonal solar water heaters are designed for use in climate conditions not requiring freeze protection Seasonal solar water heaters tend to be less solar water heater should we buy expensive than solar water heaters sold for year round use because they do not require equipment to protect the solar collectors and outside piping from extreme freezing temperatures Year round solar water heaters Year round solar water heaters are more convenient and fail safe be
12. bs on your property and from neighbouring buildings and trees If the solar water heater is to be used during the winter months take into account that the shadows are longer during the winter months because of the lower position of the sun At noontime during the winter months a six metre high tree or building can produce a shadow of ten metres or more which can significantly shade a collector mounted on the ground or a wall It is also important to note that A small systems often come with a heat exchanger and a combined solar preheat and auxiliary tank A Most medium to large systems have both an auxiliary tank and a solar preheat tank with a heat exchanger in most Canadian municipalities there are no laws that prevent a neighbour from building or planting something that could shade your collectors A The sun is much lower in the winter than in the summer Therefore a six metre tree or building can significantly shade a collector mounted on the ground or on a roof even at a distance of 10 metres A suitable roof or wall location should be about 6 m in area and should face between southeast and southwest In most of Canada excellent performance can be obtained with collectors that are mounted between 18 and 50 from the horizontal Most roofs have a minimum slope of 18 and are usually the preferred location for solar collectors If no suitable roof or wall location is available then a ground
13. d system with 6 m of single glazed flat plate solar collectors and two 270 litre 60 gallon hot water tanks Simulations were completed with WATSUN 13 2 software and use local climate data Most solar water heaters consist of solar collectors mounted on the roof of a house a pump for circulating the heat transfer fluid a heat exchanger for transferring the heat to storage and oneor two storage tanks for storing solar heated water for periods when there is no sun For more details on how energy is produced see the section entitled How does a solar water heater work on page 13 Will we always have hot water Modern solar water heaters are well suited for the Canadian climate because they produce energy when the outside tempera ture is well below freezing They also have mechanisms that protect them from freezing in the winter and from overheating on hot sunny days Nearly all systems use the existing water heater as a backup energy supply to ensure that there is always a supply of hot water Is our house suit able for a solar water heater Most solar water heaters can easily be retrofitted to your existing water heater Inside your home you will need a small space adja cent to your existing water heater for the solar heated water storage tank and the heat transfer unit that is connected to the collectors Having a storage tank for your solar heated system will reduce the likelihood that you will run out of
14. e e examine the limitations of the warranty e ask for photos or to view completed installations e inquire about follow up service arrangements e review all contracts and agreements and e obtain more than one written estimate Where do we find a dealer There are several resources you can use to assist in finding a dealer to meet your needs The Canadian Solar Industries Association and the Solar Energy Society of Canada Inc both maintain databases on dealers and manufacturers in your area Both of these organizations can be accessed through the Internet details on how to find them are provided under the section Where can we find out more about solar energy on page 18 What should be expected of the installer The Canadian Solar Industries Association CanSIA maintains a list of solar water heater installers It is highly recommended that you have your solar water heater installed by an experienced installer recognized by CanSIA When you have identified a dealer ensure that the contract documents the terms of the installation and that all appro priate permits are obtained from local authorities The contract should require the installer to start up the water heater demon strate to you that it is working as designed and show you how to periodically check its operation In addition before the installer leaves you should go through the following checklist e You are fully satisfied th
15. em Describes an add on solar water heater which can be installed with a conventional water heater Safe low temperature rating or minimum operating temperature rating Outside temperature that defines the lower limit for freeze protection of the solar water heater Solar collector A device that absorbs solar energy and converts it into useable heat Solar contribution Amount of solar energy that a solar water heater converts into hot water on an average day Solar Domestic Hot Water SDHW system Describes a stand alone residential solar water heater that is installed with a conventional water heater It is also a name sometimes used by solar specialists for a residential solar water heater Solar fraction Percentage of the total water heating load provided by the solar water heater Glossary Storage unit Tank or vessel that stores the solar heated water Some systems have only asingle tank and use the same tank for storing solar heated water and water heated with auxiliary energy Other systems use two separate tanks for storing solar heated water and water heated with auxiliary energy 17 Where can we find out more about Solar energy 18 Natural Resources Canada NRCan Renewable and Electrical Energy Division Energy Resources Branch 580 Booth Street 17th Floor Ottawa Ontario KIA OE4 Fax 613 995 0087 http www2 nrcan gc ca es erb erb or Natural Resources Canada Ren
16. ewable Energy Sustainable Buildings and Communities CANMET Energy Technology Centre 580 Booth Street 13th Floor Ottawa ON K1A 0E4 Fax 613 996 9418 Web site http www sbc nrcan gc ca renewable energy renewable energy e asp Canadian Solar Industries Association CanSIA 2415 Holly Lane Suite 250 Ottawa Ontario K1V 7P2 Tel 613 736 9077 Fax 613 736 8938 Web site http www cansia ca nergie solaire Qu bec 460 rue Sainte Catherine ouest Bureau 701 Montr al Qu bec H3B 1A7 Tel 514 392 0095 Fax 514 392 0952 Web site http www esq qc ca For more information on solar water heating systems or other types of renewable energy tech nologies visit NRCan s Canadian Renewable Energy Network CanREN Web site at http www canren gc ca Free software available to assist you in your decision Renewable energy technologies such as a solar water heating sys tem can be a smart investment RET Screen International just made it easier RET Screen International is a standardized renewable energy project analysis software that could help you determine whether a solar water heater is a good investment for you The software uses Microsoft Excel spreadsheets and a com prehensive user manual and supporting databases to help your evaluation The software and user manual can be downloaded free from the following web site http www retscreen gc ca or by contacting NRCan by pho
17. fer Circulating fluids transfer the collected energy in the form of heat to a storage tank Heat energy is transferred from the collector to the water storage tank In some water heaters hot fluid is pumped from the collector to the storage tank The pump is powered by electricity that either comes from an electri cal wall outlet or a small photo voltaic module located beside the collector In other types of solar water heaters the sun heats the storage tank directly so the fluid in the collector is heated and rises naturally to a storage tank above the collector This type of solar water heater is often referred to as a thermosiphon system It does not require an electric pump Passive solar and solar photovoltaic powered systems will continue to operate even if there is a power outage The products that require electricity from a wall outlet will not operate during a power outage 14 3 Energy Storage Solar heated water is stored in an insulated tank until you need it Hot water is drawn off the tank when tap water is used and cold make up water enters at the bottom of the tank Solar water heaters tend to have a slightly larger hot water storage capacity than conventional water heaters This is because solar heat is available only during the day and sufficient hot water must be collected to meet evening and morning requirements Determining your energy savings Follow steps 1 5 to translate the
18. he atmos phere thereby contributing to a healthier environment The energy you can expect to save by switching to a solar water heater depends on several factors such as the size of the collectors and storage tank appliance efficiency amount of sunlight in your region and very importantly the amount of water you use A typical solar hot water system will reduce annu al energy costs by 40 to 50 percent You can expect that a solar water heater will provide you with 1500 to 3000 kWh of energy per year depending on your hot water usage and regional climate The map on page 4 shows approximate energy savings for various places in Canada Example of Annual Solar Energy Contribution 0 Jan Feb March April May June July Aug El Solar energy kWh Ml Back up Energy kWh Sept Oct Nov Dec Domestic water heating contributes approximately 6 million tonnes of CO each year toward Canada s greenhouse gas emissions By installing a solar water heater you can make a difference In fact a solar water heater will eliminate up to 2 tonnes of CO emissions per year in proportion to your energy savings What is in a solar water heating system 48 Saskatoon e 49 Regina Medecine Hat op 39 Charlo fte own Fes Halifax St John London A Potential portion of water heating energy savings obtained by installing a solar water heater Figures assume a freeze protecte
19. help you select a solar water heater that meets your specific needs The dealer should provide all necessary oper ating information explain main tenance requirements and in the case of seasonal water heaters the operating temperature limits If you plan to complete your own installation the dealer should supply you with well documented instructions and fully explain the system s warranty If possible restrict yourself to dealers who can offer a warranty on both parts and labour and who have a successful track record of satisfied customers If possible ask to view a solar water heater installed by the dealer in your community Consultation with a dealer should include a visit to your home so the dealer can make an accurate estimate of the installation cost and help you make the final deci sion on where the collectors and the storage unit should be placed When choosing a solar water heater to meet your basic require ments consider the following e year round or seasonal use e best placement of the solar collector array and e size of the system Choose a solar water heater that e meets current CSA standards or will be approved by your local building inspector e has warranty coverage and e has support from a local dealer or installer 10 Your purchase should include the same considerations as those involved in purchasing any new appliance consider the dealer s reputa tion and experienc
20. ky lights Modern solar collectors are usually finished in an attractive aluminum casing with a glass cover Collectors are 10 to 15 cm in thickness and require a flat area of about 3 m each Special frames to raise the collector off the roof are usually not desirable and in most cases the improved performance of the system may not justify the additional cost On the other hand installing the solar collector at a shallow angle may compromise winter performance and will not assist in snow removal Mounting the collector flush with the roof contributes to a neat installation and ensures the collector will not contribute to additional wind or snow loading A Glazed flat plate collectors installed on a Nova Scotia home the piping be run along the outside of the house to a more convenient entry point In this case a downspout can be installed to hide the piping to avoid any negative impact on the appearance of the house The only other part of a solar water heater that may be visible on the outside of your house is the insulated piping connecting the solar collectors with the solar storage unit A good installation will pass this tubing through a special roof flashing in an unobtrusive place Sometimes cathedral ceilings or special wall construction require that y What type of Solar water heater dealers are equipped to provide you with information on currently avail able models They will advise
21. m Large e pre heat tank e greater than 6 m Equivalent2 Existing VVater Heater Tank Size Estimated Annual Energy Required by Fuel Type 180 litres 40 gallon 270 litres 60 gallon 270 litres high power output 60 gallon Electricity kWh Natural Gas m Oil litres 15 Calculating your Savings Yearly energy requirement for water heating in kWh mi or litres Portion of energy met by a solar water heating system in your region see map on page 4 Potential energy savings by a solar water heating system in kWh m3 or litres Dollars paid for energy used from a recent utility bill Amount of energy used in kWh mi or litres from a recent utility bill Estimated annual savings from a solar water heating system Example 5000 kWh Example 47 100 Example 2350 kWh Example 55 Example 600 Example 215 Your figure 16 Your figure Your figure Your figure Your figure Your figure Gigajoule GJ Unit of energy equal to 1 000 million joules 950 000 BTUs 278 kWh of electricity 25 8 litres of oil 26 9 m of natural gas or 39 2 litres of propane Solar photovoltaic panel A group of modules fastened together The modules are made up of cells that convert light directly into electricity The term panel is often used interchangeably with the term module Pre heat syst
22. mounting frame is recommended Snow coverage and the seasonal changes in the sun s position should be considered for year round installations To reduce heat loss all mounting locations should allow the con necting insulated collector pipes to pass through the roof or wall preferably at a point adjacent to the collector The pipes should be able to pass unseen through closets walls or floor spaces to the basement or hot water plumbing area Piping bundles mounted on the exterior of the house should be protected in a sleeve such as a downspout This will protect the insulation from ultraviolet degradation decrease heat losses and ensure the instal lation does not detract from the appearance of the house Some systems use piping that combines the supply and return lines and sensor wire into one bundle thereby making installation much easier Solar collectors should be installed on a southeast to southwest orientation for maximum SE performance d For best performance install collectors at an angle between 18 50 from the horizontal A Solar collectors should be positioned facing southeast to southwest Finally check that there are no zoning restrictions in your community that might restrict the placement of solar collectors Some areas might also require a building permit Your installer should be able to assist you with these issues How do we select a dealer A good dealer will
23. ne at 450 652 4621 or by fax at 450 652 5177 Canad
24. nner to leaving a car parked A ma flat plate collector sunlight is converted to heat and trapped by the in the sun with its windows greenhouse effect rolled up The temperature inside a glazed solar collector on your Trapped Hot Fluid Heat roof can easily reach 150 C when Although uncommon unglazed Each collector has its advantages there is no heat transfer fluid plastic collectors can be used and each can perform well flowing through it as a seasonal solar water heating if matched with the proper system However they are used well designed storage unit The two most common types of solar collectors used in solar water heaters are glazed flat plate and evacuated tube collectors A glazed flat plate collector consists of a shallow rectangular box with a transparent glass window covering a flat black plate The black plate is attached to a series of parallel tubes or one serpentine tube through which air water or other heat transfer fluids pass mostly for pool heating An evacuated tube collector consists of several individual glass tubes each containing a black metal pipe through which the heat transfer fluid passes The space between the pipe and the glass tube is evacuated so the air is removed A Cutaway view showing glazed flat plate solar collector components 1 Metallic Absorber 2 Glazing 3 Housing 4 Insulation 5 Heat transfer fluid inlet 13 2 Energy Trans
25. ould ask your dealer for procedures to follow when you will not be using your solar water heater for extended periods of time If you suspect a mal function contact your solar water heater dealer immediately How can we fur ther increase the e energy savings By timing your heavy hot water usage you can increase the ener gy savings from your solar water heater For example by washing your clothes early in the day between 9 00 a m to 3 00 p m you can maximize the energy savings benefits of your solar water heater As well you will give the system a chance to re charge during the rest of the day You can also introduce some simple conservation measures that will reduce your water heating bill such as e installing low flow shower heads e adding an insulating jacket to the hot water tank if it is not a high efficiency tank e insulating all hot water pipes e setting your back up heater temperature to 50 C e changing washers in leaky faucets e using lower water temper atures for laundry and e installing a separate hot water temperature booster on your dishwasher 11 What other ways can solar energy improve the qual ity of the energy we use Solar pool water heating is a common use of solar energy Unglazed plastic collectors are used to heat the pool water sub stantially reducing energy costs Solar water heaters can be less expensive than gas pool heaters Natural gas or electricity
26. se energy contributions into dollar savings Step 1 Estimate your annual energy requirement for hot water heating from the table below Read off the energy requirement of electricity litres of oil or propane or cubic metres of natural gas depending on the fuel you use for heating your water Write this value in Box 1 Step 2 Find your or one with a similar climate location or the nearest location to you on the map of Canada on page 4 Writethe percentage that corresponds to the potential portion of water heating energy saved in Box 2 Step 3 Multiply Box 1 by Box 2 Write this figure in Box 3 which is your estimated energy saving in kWh litres or cubic metres Step 4 On arecent electricity gas oil or propane utility bill find the amount you paid and the amount of kWh litres or cubic metres of fuel used If you are paying a fixed monthly rate call your utility company for this infor mation Write the amount you paid in Box 4 and the amount of fuel used in Box 5 Step 5 Multiply Box 3 by Box 4 and divide by Box 5 This is your estimated annual dollar savings from your solar water heating system Table of Yearly Energy Requirement for Water Heating Household Size in persons 2 3 4 More than 5 Average Hot Water Usage 150 litres day 225 litres day 300 litres day Suggested Solar Water Heater System Size Small e no pre heat tank e about 3 m Medium e pre heat tank e 5 6
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