Solar water heaters in California are becoming more and more popular. Human nature tends to ignore the advantages of conveniences we have and not think too hard about what those advantages entail or even how much they cost to maintain.
The average hot shower uses 17.2 gallons of water for the duration of 8.2 minutes. Your average dishwasher will use 4-8 gallons of water per cycle. The general washing machines will use between 23 and 33 gallons of water (though not always necessarily hot water) per cycle.
Just based on these estimates, you can make a safe assumption that on average per month, a three-person family or household will use about 1746 gallons of hot water a month, and this is before taking into account smaller daily activities such as washing hands or using hot water for cooking or rinsing vegetables.
Hot water doesn’t heat itself, it needs energy. For nearly everyone today, hot water heaters use electricity, rather than gas, to do the job. This is done by heating coils either in contact with the drum, inside the drum, or near the drum.
The heated water takes advantage of the ‘heat rises’ principle so that the delivery pipes near the top of the unit will carry the hot water away leaving cooler water that needs heating at the bottom near the heating elements. To maintain the heat, water heaters are also insulated in order to trap as much heat generated as possible.
During the winter, hot water is not only more necessary but requires being heated quicker and in many cases is needed simply for ‘room temperature’ water, which puts a higher strain on not only the heat mechanisms but higher consumption of energy to produce the hot water itself. This strain can put higher energy costs on something that becomes more necessary due to the weather.
Solar energy is a free form of energy that, when harnessed correctly, can produce useful energy that enriches your life and meets your daily power needs. Most people think of solar power as something that’s only in the form of solar panels or solar cells and just turns solar energy into electricity. To an extent, this is true. However, there are some specialty products that use solar energy in a very specific way. One of these specialized items that harness solar energy in California is the solar water heater.
There are three kinds of solar energy water heaters that work in three different ways:
The difference between these different types has a lot to do with the amount of water usage as well as the climates that they operate under.
A solar batch collector type, which is also called an Integrated Collector-Storage (ICS) system, heats water tanks or tubes insulated in a box and store water until needed by someone or an appliance draws from it, like a dishwasher.
The box of the solar hot water system can store water indefinitely, but has the capability of heating water too much and can present a hazard when stored and constantly heated and so they typically come with a tempering valve to protect both the storage and use of the water.
The tempering valve mixes cold water with hot water to regulate the temperature so as to avoid problems with boiling water on tap. This type is incompatible with closed loop circulation systems and isn’t especially recommended for colder climates.
A flat-plate collector is generally suited for homes in moderate climates. They consist of copper tubes fitted to flat absorber plates and configured into a series of parallel tubes connected at each end by two manifolds. The plate is contained within the insulated box and covered with tempered glass and can just two can maintain hot water for a 40-gallon tank which can handle hot water needs for two people with just two plates.
Evacuated tube collectors are the most efficient and work almost like thermos. A vacuum space separates the inner collector tube and outer glass tube which serves both to insulate the inner tube from cooling and allow outer heat inward. These kinds of collectors can operate in nearly any kind of weather, as low as -40° F. Their only real drawback is the pricing as they can cost twice as much as a flat plate collector to heat the same amount of water.
There are four kinds of circulation systems used to transfer heat to stored water inside of the solar hot water heater:
The main difference between these systems involves whether the collector panels are heating directly the water to be stored or using a system of heat-transfer to carry heat from water exposed to the solar collector to the storage via a heat exchange mechanism.
Active systems use a motorized pump to transfer heat through a heat exchanger and thus typically could be considered inefficient as a way of saving money, unless the motor is solar powered as well; the motor requires power to keep the water flowing from the collectors to the heat exchange.
A passive system uses the natural properties of heat, much like traditional water heaters, in that the heat itself is used to move the water through the system and uniformly heat the entire storage tank for use.
At Small Energy Bill, we realize not everyone is going to have an engineering degree to answer these questions and not everyone’s home or commercial building have the same needs for hot water. Our own specialists and technicians are here to answer any questions you have about solar water heaters and what kind best suits both your needs and your premises.
Call us for a free consultation with our experts. We can even answer questions about tax rebates and incentives offered in your area for switching your home over to solar power and other clean energy solutions to maximize your energy efficiency while maintaining comfort.