With solar power increasing in popularity, so are solar hot water systems. There are several major benefits to using one of these systems. Notably, your carbon footprint will be lower, and you will spend less money on your electric bill. At the same time, you will not have a problem delivering hot water in high volumes to any source in your house.
Before we will dive deeper into the details, let’s understand the basics. The video below will help you to understand, how to identify the setup for a hot water system.
Understanding Why Solar Panels Have a Peak Power
Every time a solar panel is created it undergoes a series of tests to determine its power output. The test conditions used to determine the peak power of a solar panel are a light intensity of 1.000 W/m^2, a standard airmass of 1.5, and a temperature of 25 degrees Celsius. Additionally, the solar panel is positioned so that the sunlight is hitting it perpendicularly.
The results of the tests provide the manufacturer with the panel’s peak or nominal power. When these testing conditions are used, the peak power will be the same no matter where the panel is located. You should note that the peak power of a solar panel can have a range of 5 percent higher to 3 percent lower than the listed power.
Solar Water Heater Vs. Electric Water Heater
Those of you that are thinking of switching to a solar hot water system probably have an electric water heater at the moment. As a result, it is important to compare the two so that you can determine whether it is in your best interest to make the switch.
Solar Water Heater Power Consumption
One of the biggest benefits of switching to a solar hot water system is that you will significantly reduce your power consumption. While there are significant start-up costs, once you have the system installed, the energy costs will be almost nothing. Zero electricity is required to run solar water heating systems, so the overall power consumption at your house will be significantly reduced.
Conventional Water Heater Power Consumption
As you very well be aware, conventional water heaters consume a significant amount of power. On average, conventional water heaters are responsible for 25 percent of the power consumption in a household according to the United States Department of Energy.
Comparing Costs of Solar and Traditional Water Heaters
When most people are trying to figure out if they water to switch over to a solar hot water system, they ask how much it costs. The general population seems to think that solar hot water systems are more expensive than traditional systems. While there is some truth to this, it is a little more nuanced of a situation.
The amount of money you need to spend to get a solar hot water system installed is far more than it is for a traditional system. You can expect to spend somewhere from $2500 to $3000 on initial costs. Whereas traditional systems only cost around $400 to install. As a result, you will be out of pocket when you first go to install the system.
While you will lose money at first installing a solar hot water system, you will save money in the long run. Firstly, solar water heating systems last much longer than the traditional heating system. You can expect your solar system to work effectively for 20 to 30 years. Conversely, a traditional water heating system cannot be expected to perform at its best for more than 15 years. As a result, you will save money replacing the system in the future.
Finally, solar water heaters are extremely cost-effective when it comes to utility costs. While there will be a small cost to keep them running, it will not be anywhere close to how much it costs each month to run your regular water heater. As we mentioned above, you can expect your water heater to be responsible for 25 percent of your electricity bill each month. If you reduce that to 5 to 10 percent, the money you save will quickly pay for the start-up costs.
Environmental Impact of Solar Energy Vs. Electric Systems
While the environmental impact might vary in importance depending on who you are, it is certainly something to consider. As you might expect, traditional water heating systems at more to your carbon footprint than solar hot water systems. This is because when solar panels are used as a replacement for fossil fuels, fewer pollutants are released into the air. As a result, your water heating system will be more eco-friendly.
Notable Detriments for Each Solar Water Heating System
There are a few other factors that you should be aware of that are not directly comparable between the two system types. Traditional water heating systems can sometimes short circuit as a result of the cables and cords involved to keep it running. This can prove to be dangerous for the user when they are making adjustments to the system. This is not an issue for solar heating systems.
Short-circuiting is not a problem for solar hot water systems because they are roof-mounted, and as a result, they are not connected to any wires. However, this causes its own set of problems. Notably, your solar system is exposed to the elements, which means that they can be damaged by rain, snow, and other extreme weather. The biggest risk is corrosion from humid weather. This is obviously not a problem for electric water heaters.
Are Solar Hot Water Systems Dependent on Climate?
A common misconception about solar power is that you will not have power when the Sun is not out. Fortunately, that is not something you need to worry about because solar heating systems always come with a backup heater. The backup heater will be powered by gas or electricity. As a result, when there is a cloudy or snowy day, you do not need to worry about running out of hot water.
With that said, solar heating systems are more cost-effective when you live in a sunny area. As we mentioned above, solar heating systems are expensive to install, but they make up that money by reducing your monthly water heating bills. You will not save as much money if your system is constantly switching to the backup energy source. As a result, it is not always recommended to install a solar water heating system in areas that do not get a lot of Sun.
Solar Hot Water Systems Are Only for Water
Although it says that it is a hot water system in the name, you might think that you can install it so that it will help power your other appliances. Unfortunately, that is not the case. Solar hot water systems will only provide hot water for you, and they will not power your other appliances. If you want to use solar power to power the rest of the high-efficiency appliances in your house, you will need to install a photovoltaic solar energy system.
Active Vs. Passive Solar Water Heaters
There are currently two major versions of solar water heaters, and each has two subtypes. Active and passive solar hot water systems each have their pros and cons.
Active Solar Water Heating Systems
Active solar water heating systems move heated water from its solar collectors to your house via a pump. Typically, people that live in cold climates install active solar water heaters. This is because excess water is stored in an expansion tank that is kept inside to ensure that it does not freeze. There are two subtypes of active solar water heaters.
Direct active systems directly heat water in collectors. The water will then be transferred to your hot water tap, showerheads, and other water sources. In most of these direct systems, you will find that the collectors are made of metal or glass.
Conversely, indirect active systems heat up a heat transfer fluid such as propylene glycol in the solar collectors. Heat is then transferred with a heat exchanger to the storage tank where the water is being held. Unfortunately, with this type of heater, there is a chance that you will lose some heat during the transfer process.
Passive Solar Water Heaters
The most notable difference between active and passive solar water heaters is that they do not use circulating pumps to transfer heated water. Instead, they use convection to naturally circulate the water. This means that the hotter water will rise to the top, whereas the cold water supply will sink to the bottom. This ensures that the water circulates, and it remains hot throughout the tank.
You can choose to install an integral collector solar water heater if you want your water to be heated directly by sunlight. These systems have large, black storage tanks that are built into an isolated box. The sunlight keeps the water warm at all times before it is sent through the pipes and your plumbing system when you require hot water.
Finally, you can get a passive thermosyphon system installed. These systems use flat metal plates to heat tiny sets of water on the roof of your house. So, when you unlock the pressure relief valve, the hot water at the top of the solar collector will flow down from the tank to where you requested the water. Typically, these solar thermal systems are built to hold 40 gallons of water at a time.
How to Figure Out Which Solar Hot Water System Is Best for You
As you can see, there are several types of solar-heated water systems for you to choose from. While having variety is great, it can be difficult to figure out which system is best for you. Each system has its own pros and cons, and you need to factor all of them in before you make your decision.
You should look to purchase a direct system if you are in an area that does not experience a lot of cold weather. Specifically, if the temperature rarely drops below freezing, direct heating systems can be very effective. Conversely, if you live in cold climates that experience a lot of freezing weather you might be better off with an indirect active system. These systems are less likely to experience damage from cold temperatures.
If you need your system to generate hot water at double the rate, you should consider investing in a system that circulates indirectly. These systems are perfect for people that have pools or hot tubs. You will be able to regulate the temperature of your swimming pool, and you will not need to worry about running out of hot water when you are showering.
Integral passive systems are best for households that use a lot of hot water during the day. This is because this system produced several small sets of warm water. As a result, you will not need to be anxious about running out of hot water if you are the last one to take their morning shower.
Finally, one of the biggest decisions you have to make is where you will install the solar panels. Depending on the amount of land you have, you might be able to install the panels on the ground. However, most people do not have that luxury, and as a result, they need to install the heater on their roof. If you purchase a thermosyphon solar water heater, you will not need to worry about having enough roof space. Additionally, you will have extra space to walk around in your backyard.
Rebates and Incentives for Installing a Solar Heating System
When you go to purchase your first solar water heating system, it will be easy for you to get caught up on the base price. However, as we mentioned earlier, there are long-term financial incentives for installing a solar thermal system. That being said, there will be some more immediate incentives for people living in the United States.
People that install a solar water heating system will benefit from the federal solar tax credit. This credit provides people that install solar heating systems with a refund on 26 percent of the installation costs. So, a $3000 solar hot water system will only cost you around $2220. You will receive this tax credit when you do your taxes at the end of the tax year.
Furthermore, many utility companies offer unique discounts to people that install these types of heating systems. That being said, the rebates and discounts are not consistent in any state, and as a result, you will need to look up what your local utility company will offer you.
Types of Solar Collectors
We mentioned them a few times while looking at the pros and cons of solar water heating systems, but you might not be aware that there are several types of solar collectors. In total, there are three types that these systems use.
Evacuated Tube Collectors
An evacuated tube collector is a solar collector that is available in the direct flow and heat pipe configurations. The heat pipe variant has multiple rows of transparent tubes that are vacuum-sealed. These tubes have a metallic coating that is used to absorb as much of the Sun’s heat as possible. This heat is then transported to an aluminum fin which heats the copper tube in each of the glass collector tubes.
Additionally, there is a solution of alcohol inside each of the copper tubes that are vaporized which causes the condenser bulb at the end to get extremely hot. Heat is transferred from the bulb to the water stored in the manifold. This water can be sent into storage tanks or directly into your house.
The direct flow version of evacuated tube collectors differs from the previous version in that it has two copper pipes that run through the middle of each tube of glass. One of the pipes is for incoming water, whereas the second one is a return pipe for the heated water. If you open up the system, you will find that there is a heat-absorbing plate inside the tube that provides the physical separation that is needed between the incoming and return pipes.
Flat Plate Collector Panel
A flat plate collector panel is a shallow aluminum-framed sealed box with an absorber player. The flat plate collectors have a dark coating behind the glass cover to help absorb heat. Behind the absorber are copper pipes that allow the water to flow. The absorber plate is heated by the sun’s energy whenever it is out, and that heat is transferred to the pipes.
Inside the flat plate collectors, water is heated from the bottom to the top. Hot water rises to the top, and as it cools it sinks to the bottom so that it can be reheated. As a result, the water in the tank is kept hot at all times. When water is called for from your flat plate collectors, it is drained from the bottom so that the recently heated water is sent to your faucets.
Integrated Collector and Storage System
Finally, an integral collector storage system has several wide tubes or a black tank inside an insulated box. The black surfaces will absorb heat from solar energy and heat the water inside. Water is stored inside the tank until it is requested by someone at the house. This is the simplest of the three solar collectors. In fact, it is fairly simple to make yourself if that is something you are interested in doing.
How Many Solar Panels Will You Need?
You might be worried that you to purchase several solar panels to make sure you are gathering enough solar energy to run your hot water system, but that is not the case. You only need one solar panel to generate enough energy to keep as much hot water as an electric heater. So, there is no need to purchase several solar panels to heat water.