Solar Water Heating Reduces CO2 Emission
Solar Collector Inc., solar collectors are reducing CO2 emissions by more than 13,000 tonnes / 28.6million pounds per year, with collectors installed in the UK, USA, New Zealand, Germany, France, Sweden, Italy, Hungary, Australia, Canada, Mexico and many other locations. (One metric ton = 2200 pounds)
There has been a great deal of information in the media over the past few years about global warming and the role of CO2 emissions. 2003 saw extreme weather conditions and a heat-wave throughout Europe, clear evidence of the realism of this problem, commonly referred to as the "green house effect." Burning fossil fuels such as coal for electricity production, and gas for water heating both release large amounts of CO2 into the atmosphere, thus contributing to this environmentally harmful phenomenon. By using renewable energy sources such a Solar Thermal, Solar PV, Wind, Hydro and Geothermal, reliance on fossil fuels can be minimised, thus directly reducing CO2 emissions. On average for every 1kWh of energy produced by a coal power station, 1kg (2.2pound) of CO2 is produced. Burning natural gas for electricity production or water heating produces about 450grams of CO2 for every kWh of energy produced. In the average household, water heating accounts for around 30% of CO2 emissions. By installing a solar water heater, which can provide between 50-70% of your hot water heating energy needs, you can reduce your total CO2 emissions by more than 20%.Below are two calculators which can be used to estimate how much you can reduce CO2 emissions by installing an solar water heater together with either an electric or natural gas water heater. Just enter your average annual insolation level and number of evacuated tubes and click on calculate.If you dont know how many evacuated tubes you require, please Contact us.
When determining what size collector you need, you must consider two key factors: insolation level and energy requirements. Energy requirement will usually take into consideration the volume of water and rise in temperature required. Once you know these factors you can determine the size collector you require. The bigger the collector you have, the more hot water, but you should make an economically sound decision. Generally it is wise to select a size which will provide you with 90% of your hot water needs in the summer.Although it may seem strange to use a value of only 90% for summer solar contribution, it is for good reason. It is normal to size based on 100% of your summer hot water energy needs, with a percentage provided throughout other months, lowest obviously in winter. That is based on normal water usage, but often, and particularly in the summer, water usage patterns may not be that normal, with cooler than normal showers taken in hot weather, and greater possibility of the house being vacant for one or two days each week (weekends). So, using a target value of 90% will probably actually result in a system that is able to supply more than 100% of your hot water needs in the summer, without excessive heat production, which can lead to water loss via pressure release and a waste of energy.
Depending on your preference, either Metric or Imperial values may be used to calculate the number of tubes required. Please note: 1 kWh/m2/day = 317.1 Btu/ft2/day *Water Volume = This should represent the actual volume of hot water used at the tap in total each day. Although most hot water systems have target temps of 60oC / 140oF, when showering a temperature of between 42oC / 107oF and 45oC / 113oF is normally used. Therefore 300L of hot water at the tap may only draw 220L of hot water (at 60oC / 140oF) from the storage tank.
Please note:
The calculator below can help to determine how many evacuated tubes you require given your energy requirements. Solar collectors come in a set of standard sizing of 15, 20, 30, or we can also make 10, 25, as you order, depending on your region. Of course you can also combine collectors to increase the size. If you get an answer that is not a standard size, as a general rule, select the next size down - this will prevent having too much heat in the summer.
**Temperature Rise = target tap hot water temp - average mains cold water temp.Target hot water temp should usually be around 42oC / 107oF to 45oC / 113oFCold water usually fluctuates by about 10oC / 18oF between winter and summer. A check of your local weather records should provide you with an idea of average cold water temperatures ( about 10oC / 50oF in winter and 20oC / 68oF in summer, in mild regions).
Apart from the three key factors used in the calculation above, you may also need to consider:1. Annually/daily shade patterns 2. Angle/direction of installation (a less than ideal angle will reduce efficiency)6. Installation site (Do you have enough room for the collector(s)?)
Using this energy calculator you may determine how much energy a Solar Collector Inc., solar collector will produce each day/month/year. The way you utilize this energy is up to you. You can heat water for showering and washing clothes, or central heat a building. In fact one integrated system can complete both these functions.You can also use these values to help you calculate how much energy you can save by using our collector.In order to calculate energy output you must input the following variables:
Insolation Level - Before you calculate your energy output, you must know your solar insolation level. There are available from the insolation page. Take note of your max and min levels throughout the year as well as the annual average value. When assessing potential energy savings, input annual average insolation, and take note of the "per year" energy output value. Energy must be input in the unit kWh/m2/day. 1 kWh/m2/day = 317.1 Btu/ft2/dayCollector Size - You must enter the collector size in absorber surface area.The absorber surface area of the various tubes sizes are as follows:- 58/1800 = 0.08m2 per tube. Therefore a Solar Collector Inc., SCM20-58/1800 collector = 1.6m2 absorber area- 58/1500 = 0.067m2 per tube
Energy Cost - Enter cost per kWh in your local currency (may need to convert from m3 or Therms)1 therm = 29.3kWh = 100,000Btu = 105.5MJNatural Gas is 39MJ/m3 = 10.83 kWh/m3LPG Propane (liquid) = 25.3MJ/L = 7kWh/LLPG Propane (gas) = 93.3MJ/m3 = 25.9kWh/m3
Collector peak efficiency is only achieved when ambient temperature and water temperatures are the same. During normal use, this is only likely to happen for a short period of time each day, and usually only when ambient temperatures are high (summer). Therefore during normal use, the solar collector can not always perform at such a high level of efficiency. This is true for all evacuated tube and flat plate collectors, not only Solar Collector Inc., solar collectors. In order to provide more realistic figures, the above calculations are based on "normal" operating conditions under which the difference between ambient temp and manifold water temp is around 30-40oC.- When making comparisons with other products please take the above point into consideration. Do not simply use the peak efficiency values for energy output, as this will provide inflated figures. - Monthly and annual values are calculated using 28 days and 336 days respectively to account for days of very low solar radiation.- Energy output values are approximations. Actual energy output and overall system efficiency will depend upon installation location, climate, insulation, system configuration and many other factors. On rainy or heavily overcast days energy output will be greatly reduced.- Energy is produced in the form of heat. In transporting and converting this energy, such as for air conditioning or central heating, some energy (heat) will be lost, as no system or insulation is 100% efficient.
