In the Philippines, the average period of sunlight is 8 hours a day, so solar systems are efficient, in addition to practically not depending on auxiliary methods for heating. The solar water heater is an alternative to reduce electricity costs.
How does the solar water heater work?
Solar energy is collected by panels and then converted into heat. The heat heats the water which after being heated is taken to the reservoir and will be available for use. Inside the solar panels are the fins, which are the components responsible for capturing and transforming energy into heat. The water contained in the pipes will be conducted to the reservoir, called a boiler.
The pipes inside the system are usually made of copper, and painted in dark colors. Paint enhances the heating effect. A necessary precaution to be observed before installing the system is the dimensioning of the water reservoir.
The sizing should consider the number of people using the system the average duration of baths and the use of heated water. The water reservoir, called the boiler, will prevent the loss of temperature of the water stored inside. The fact that it conserves the temperature allows you to use the heated water even in periods without the sun!
What are the system variations?
When I talk about solar water heating, the fundamental changes are the circulation types within the system. Water conduction can be thermosiphon or forced circulation. Check out the difference between the two!
Thermosyphon circulation
This system is based on the laws of physics in which hot water naturally rises, and cold waterfalls. Therefore, in this system, the reservoir must be positioned above the water-collecting plates. Due to the difference in density between hot and cold water, there is natural circulation and accumulation of hot water in the thermal reservoir.
Forced circulation
In forced circulation, the storage tank can be physically distant from the solar panels and can even be located below the collection system. Electronically controlled pumps will do the conduction of the water.
What are the system elements?
The solar water heating system is simple and consists of the following elements:
Solar panel — piece responsible for transforming radiation into thermal energy. The panels receive solar energy and convert it into heat through fins;
Hydraulic circuit — piping, parts, valves, and pumps responsible for circulating water, from collecting solar panels to distribution in the system;
Reservoir — also called a boiler, can be made of copper, stainless steel, or polypropylene. The boiler will always be insulated to ensure that the temperature of the water inside is maintained.
The solar water heater is an easy-to-install system that provides savings and gains for the environment.
How to choose the ideal water heater
There are electric, gas, and solar heaters. Electric ones are used in showers and faucets through electricity. Gas heaters, which can be instantaneous or pass-through are similar to electric ones and heat water using small gas flames.
Solar panels are made up of large plates, usually placed on the roof, which reuses sunlight to generate energy and heat water. All have their advantages, which should be considered according to your usage needs.
Electric heaters do not use gas or fire for heating and are, therefore, non-polluting. Not to mention that the energy supply is automatic and constant, ensuring precision in controlling the volume and temperature of the water.
Gas heaters have better water pressure than electric models and save 60% to 85% compared to similar electric ones. Solar heaters are more expensive but provide significant energy savings. They use clean, safe, and ecological energy, have simple installation, and have better thermal efficiency in addition to being able to be used collectively.
What are the types of gas heaters?
By passage, where the water is heated gradually, as it passes through the device. By accumulation, where heating occurs through the passage of water through a system of coils, having a reservoir by accumulation.
What precautions should I take with a gas heater?
The environment needs to be ventilated, with constant renewal of air, as the heater burner consumes oxygen during combustion. Never eliminate or reduce ventilation in these environments. Burning gas in the heater also generates harmful substances which must be disposed of through the chimney. It is recommended to periodically check the state of the chimney.
How does a solar heater work?
The solar heater absorbs solar radiation, transforms it into thermal energy, and then heats the water stored in the system. It consists of two main components: solar collectors (plates or panels, usually placed on top of the property) and thermal reservoirs (or boilers). Its use is a renewable, inexhaustible, and free energy source, in addition to being non-polluting.
1. Pass-through heaters
In these heaters, water is heated as it passes through the equipment. When buying a heater, the most essential specification to pay attention to is the capacity, measured in liters per minute (l/min). That is, how many liters of water the heater is able to heat each minute.
We can find heaters ranging from 6 l/min to more than 25 or 30 l/min on the market. To know which one to use, it is essential to count how many points the heater will serve and what is the average consumption of these points.
A good shower, for example, consumes between 10 and 12 l/min. As the water we use is mixed with cold water, a heater of about 6 to 8 l/min is suitable for a shower. But, if we want to use a faucet simultaneously, it is interesting to increase the heater capacity a little, to something around 10 l/min.
If the heater has to serve more than one bathroom, we must count the number of points (showers, taps, and hygienic showers), add the consumption and then choose the device with the appropriate capacity. For example, for three showers that can be used simultaneously, it is recommended to have a heater with a capacity of at least 25 l/min.
We must also remember that these values are the most common. However, there are showers with more than 20 l/min capacity on the market. They are those showers with solid intensity and to heat all that water flow, bigger heaters are needed.
2. Accumulation heaters
Whether electric, solar, or gas, storage heaters work in a similar way: a hot water reservoir will supply consumption. This system is indicated for places where there is a large consumption concentrated at a specific time of the day, as, for example, in the case of several bathrooms being used at the same time or having a large capacity bathtub. In such cases, pass-through heaters may not be sufficient.
But, basically, the following calculation should be made: how many people are in the house and how many liters each one uses per day.
So, for a house with five people, the electric heater should produce about 225 liters of hot water per day (5 people x 45 liters per person). In the case of a gas heater, this figure drops to 200 liters and, in the case of a solar heater, it reaches around 250 liters.
With these numbers in hand, you can choose the heater. Devices of 150, 175, 200, 250, and 300 liters are pretty common, but there are other sizes, ranging from 50 to 1000 liters. For the examples above, heaters in the range of 200 or 250 liters are sufficient.
When applying the formula, we should also check for special equipment that can significantly change consumption. Large-capacity bathtubs require larger heaters. A bathtub with a capacity of 200 liters, for example, requires a heater with a capacity of 100 liters more per day.
3. Solar boards
Finally, in the case of solar heaters, the question is to size the number of plates. The calculation must be done according to the formula above to identify how many liters of water must be heated.
With the calculation of the volume done, check the table of solar plate manufacturers. There are two main models on the market: those measuring 1.42 m², with a capacity of 103 liters per day, and those measuring 1.95 m², with a capacity of 104 liters per day.
Therefore, in the example above, in which we needed 250 liters of hot water, we have 250 / 103 = 2.42 (considering the plates of 1.42 m²). That is, for this residence, we will adopt three collector plates of 1.42 m² each, in addition to a complementary reservoir of 250 liters.
Again, as all these technologies are developing rapidly, it is always important to check with specialists in the field the types of heaters that are most efficient, economical, and have the most negligible impact on the environment and, from there, carry out their correct sizing.
Reasons to install a solar heater in your home
1. It’s economical
One of the most desired advantages of the solar heating system is the economy. No wonder the reduction in the value of the energy bill is enormous. You can save around 40% on your electricity bill. Thus, over time, the amount invested in this technology is compensated by decreased expenses.
This is because, when replacing one of the villains in energy expenditure at home with solar heating, the electric shower, for example, electricity consumption drops.
2. Value the property
Who wouldn’t want to have a property with an energy system that sharply reduces expenses? So, it is a fact that this technology values your home. And it’s not little! Not only for providing savings but also for sustainable ethics.
The solar thermal energy market has been growing in the Philippines and even more in the world. Having a solar heating system on your property will still be indispensable! Especially when there are significant increases in bills. For these reasons, more and more buyers are giving preference to properties that have a solar heater.
3. Preserve the environment
Now, one of the main reasons for the importance of solar heaters. They considerably reduce damage to the environment. It is possible to eliminate waste from this system in a simple way, which avoids pollution. In addition, the solar heater is installed in your home, and there is no need for a large area to produce this energy, avoiding deforestation.
Now, perhaps most importantly, solar thermal energy will also not require processes that cause the emission of polluting gases, which contribute to the greenhouse effect. In addition, the solar heater reduces the use of electricity, such as the shower, which represents about 40% of electricity consumption in homes.
4. Inexhaustible energy
Do you know what an inexhaustible source of energy is? As the name implies, solar thermal energy is an endless source since it depends exclusively on sunlight. In addition, it is the most stable energy among wind and water energy.
5. Solar heater durability and comfort
The durability of this system is a very advantageous factor. With an average useful life of 20 years, it is not only able to pay off the investment, but also reduce expenses for several years after it is paid off.
But it doesn’t end there. Along with this durability, there is the comfort that this system provides. Who never, during the winter, closed the shower valve until there was very little water left? So it is! We do this so that the electric shower can warm the bath water more.
With the solar heater, the water heating system ensures that your bath is much more comfortable. That’s because the amount of heated water is very abundant!
6. Low maintenance
In addition to the previous reasons, the solar heater still requires minimal maintenance. This maintenance is an annual cleaning and inspection to ensure that the solar collectors are in good condition.
This maintenance is recommended every 6 months to prevent dust accumulating on the plates from impairing light capture.
Why is a solar water heater worth it?
Many people opt for the solar water heating system because of the savings directly felt in their pockets. That’s because the return on investment pays off a lot! For you to better understand how this account is, I will explain in this post.
First of all, it is interesting to evaluate the initial investment made. The cost of installing a solar water heating system is a little higher compared to the electrical system, and very similar to that invested in the gas mode. The big difference is in the maintenance cost — and that’s the catch! With an average durability of 20 years, the solar heating system demands a very low maintenance value.
Maintenance basically consists of washing the collector plates twice a year with soap and water. Although the initial investment is a little higher, the maintenance cost is advantageous.
The big savings in your pocket are already being felt in the first months of installation. This is because by heating the water with sunlight, the establishment will save on the electricity bill (since the shower can represent up to 40% of the total amount spent on the energy bill). Depending on water consumption, the return on investment (also known as payback ) can occur in about two years.
And anyone who thinks that this is advantageous only for homes is wrong. This relief in bills is also felt in establishments such as industries, hospitals, clubs, hotels and motels.
So it’s worth the investment if you have some money saved in savings and you still don’t have a solar water heating system. The return with savings on the electricity bill will offset the initial investment made.
How long does a solar water heater last?
Durability is an attribute that stands out when it comes to a solar water heating system. Just to give you an idea, some models were installed 30 years ago and are still in operation.
But for this to happen, care and zeal are essential in a very important step. Maintenance. After all, the quality of the water and the periodic maintenance of the equipment directly impact the proper functioning of the system.
It is recommended to wash the solar collectors twice a year with soap and water. This task should be carried out when the weather is milder, in the early hours of the day or the late afternoon. That’s because the plates tend to get cooler and less likely to suffer a thermal shock.
It is essential to say that plates with accumulation of dirt can directly compromise the system’s performance, because they can reduce the passage of sunlight.
It is also valid to always check the integrity of the glasses because if they present cracks, they will allow the passage of water, considerably reducing the efficiency and useful life of the equipment.
Another preventive maintenance that must be carried out annually is the drainage of the system to verify that there are no obstructions in the system pipes, mainly due to impurities from the water originating from the supply concessionaire.
By having this attention, it is possible to enjoy the benefits most praised by the owners of this system. The first one is the savings generated in your pocket.
Depending on water consumption, the return on investment made can occur in about two years. This is because using sunlight to heat water used in showers, sinks, and laundry represents a good saving on the electricity bill. Some consumers already feel a significant relief from the first months of installation.
How to clean your solar water heater system
In this section, I have gathered tips that you should take to take care of your solar water heating system with all care.
1. Glass washing
Every six months, washing the glass of the solar collectors is necessary. The process is straightforward and involves water, detergent, neutral soap, and a fur broom. Rub the glass carefully so as not to force it. Always wash in the early morning or late afternoon when the sun is not too hot. This will prevent the glass from breaking due to thermal shock.
2. Air bleeding
The existence of air in the pipes can impair their functioning. One of the “symptoms” of this is the drop in system performance and also the temperature of the water return pipe of the collector plate assembly. Observe if the temperature is getting colder as the pipeline reaches the reservoir. If you notice this, there is a strong indication of an air bleed. To resolve the issue, follow these instructions:
– Close the drawer valve or ball of the return pipe to the reservoir
– Open the air vent cap or the manifold outlet union
– Let the water out for approximately 1 minute
– Close cap or union
– Reopen the registry
It is important to say that in pumped systems, the air vent must be opened with the pump running, allowing it to leak for approximately 1 minute. Only then close it again with the pump still running.
3. Draining the system
It is advisable, at least once a year, to drain the entire system. In regions with very cloudy water or a high iron content, the ideal is to repeat this procedure every six months. Follow these guidelines:
– Shut off the cold water supply from the reservoir
– Open the drain plug or the union on the bottom of the plates
– Let it empty completely
– Open the cold water supply from the reservoir
– Let the water run for a few minutes.
– Close the drain plug or union
If you notice that the water flow seems obstructed when draining, seek authorized technical assistance for special internal cleaning of the equipment.
4. Replacement of resistance
In case of burnout of the electrical resistance, which acts as an auxiliary system, change the accessory following these recommendations:
– De-energize the system
– Drain the system to just below the resistance level
– Disconnect the resistor terminals
– Unscrew it with a suitable wrench, not damaging the reservoir.
– Screw in the new resistance using thread sealant or similar
– Release the water supply to the reservoir
– Check for any leaks. If they exist, seal them.
– Reconnect the cables and re-energize the system
– When replacing the electrical resistance, observe the specifications recommended by the tank manufacturer.
5. Thermostat replacement
It is important to follow these procedures in case the thermostat burns out or breaks down. Check it out:
– De-energize the system
– Disconnect the thermostat wires and remove it.
– Place the new thermostat, taking care to attach the temperature sensor bulb correctly
– Reconnect and re-energize the system
– Test operation and adjust the thermostat dial between 40°C and 45°C
– When replacing the thermostat, observe the specifications recommended by the tank manufacturer.
6. Replacement of broken glass
In case the solar collector glass breaks, the procedure is simple. However, the ideal is for the installer to carry out the exchange (since he has experience handling the collector). The procedure he will perform will be this:
– Remove the aluminum angle from the edges of the glass (some solar collector models have this angle, which is a kind of seal and will be unusable when changing the glass)
– Remove broken glass by cleaning around the edge of the collector box
– Apply the silicone to the corners of the collection box and place the new glass
– Apply silicone along the entire edge of the glass
– Replace the aluminum angle bracket (if it is a collector model that uses an angle bracket). You can easily find it in commerce;
– Let the silicone dry
What is the ideal piping for a solar heating system?
When deciding on a solar heating system, it is necessary to consider the different types of piping. Especially because hot and cold water will pass through them, they need to be adequate.
For this choice to be very assertive, I have gathered the main types (PVC, PPR, Copper, and PEX) and which recommendation applies to each of them — do not be alarmed by these nomenclatures, I have tried to make it very simple for you to understand, all good?
1. Polyvinyl chloride (PVC)
Tubes of this type are indicated for conducting cold water with a temperature of up to 20°C. The most common diameters of PVC pipes are: 20mm, 25mm, 32mm, 40mm, 50mm, 60mm, 75mm, 85mm, and 110mm. Although it is a material most used for residential plumbing installations, it has low resistance to high water pressure.
2. Solderable PVC (usually brown in color)
Uses adhesive and cleaning solutions to integrate the pipes with the fittings. The screw-on version is available in a lighter color. For this type, it is common to use thread-sealing tape to establish the connections.
PVC material can also be used for sewage. The most standard diameters are 40mm, 50mm, 75mm, 100mm, 150mm and 200mm. In these variations, there are also two versions: the white one, for normal use; and the most reinforced, light gray.
3. Polypropylene Random Copolymer (PPR)
This type of tube is resistant to high pressures and temperatures — it can withstand peaks of 70°C. It does not suffer corrosion, and its tubes and connections are connected by thermofusion (with the help of a device).
Thus, these parts form a single pipeline, which reduces the possibility of leakage. Its tubes have diameters from 20mm to 110mm. Its downside is that it requires installation equipment and more clamps than copper piping.
Copper
Tubes of this type are very resistant and are indicated for high temperatures (they support the passage of water above 100˚C). In addition to easy handling, they are weldable and use few clamps.
For hot water use, thermal insulation and expansion joints are required. A point you should be aware of: when installed in an apparent way, they can suffer corrosion—the diameters of copper tubes from 15mm to 104mm.
4. Monolayer Cross-linked Polyethylene (PEX)
PEX pipe is different from other types. This is because their connections are metallic (in brass) of the sliding type, and their gauges are much smaller than the others.
Therefore, they are very suitable for drywall walls and buildings with similar environments, such as hotels. The main difference, in this case, is that the water comes to the distributor module through the plumbs, and from there, it feeds each point individually.
PEX tubes resist high pressure and conduct cold water and hot water (supporting up to 95°C). The disadvantage is that it uses more clamps than copper tubes when installed in an apparent way. The diameters found on the market are 16mm, 20mm, 25mm and 32mm. And, like any other hot water pipe, it is essential to install thermal insulation to maintain the temperature.
FAQ About Solar Water Heater System in the Philippines
Solar water heating still raises many questions here. From how this system works in practice, the cost involved, the return you get, and so on. To help you better understand the subject and learn about the benefits of solar heating, I have gathered the most common questions.
1. Is the installation of the solar heater system too complicated?
No, it’s not complicated. Basically, the solar water heater system comprises two essential items: the solar collectors, or plates, and the thermal reservoir. In some installations, it is necessary to use pumps to circulate the water in the solar collectors.
2. Does it pay to install solar heating anywhere?
Yes, it pays off and a lot! Be it residence, business, hotel. Any establishment that uses heated water can install this system to avoid using electricity to heat water. No matter the size of your business, there is always a way to meet your needs.
Before installation, however, specialists visit the site to get to know the terrain and make sure that there are no shading areas, that is, trees or very tall buildings close to the desired location, which could make the installation unfeasible.
3. When can I install solar heating?
Many wonder if installing the system in new works is only possible. And the answer is no! Any work, even if it is older, can have the installation of a solar water heater. It is only important to pay attention to the necessary piping, an essential item for properly functioning this mechanism.
4. Is the cost too high to install this solar heater system?
Considering gas and electric systems, solar water heating has a slightly higher cost. But the biggest advantage is in the maintenance value. Therefore, the initial investment can be recovered in a short time (an average of 2 years, depending on your consumption). Just to give you an idea, some existing users manage to reduce their electricity bill by up to 40% when using the solar heating system.
5. Do I only have heated water on sunny days?
This is one of the most frequent questions asked by customers looking to learn more about solar water heating. As this system acts as a thermally insulated water reservoir, there will still be heated water even if the day is cloudy. With just a few hours of sunlight, it is possible to heat the entire contents of the reservoir and thus renew the supply.
In any case, it is recommended to attach an auxiliary heating system to the installation, be it gas or electric, for periods when the sun does not appear so often.
6. What happens to the water at night?
The thermal insulation of the reservoir allows the water to remain warm for a period. With this it is possible to have warm water for a good bath at any time of the day (or night).
7. What return can I have with solar water heating?
There are two clear benefits: The first of them is saving your electricity bill, which can be reduced by up to 40% of the value, depending on the consumption you have at the installed location. The second is about your environmental awareness: you will contribute to the planet, as it is clean energy and has no impact on the environment.
8. Does solar water heating generate energy?
No, solar water heating does not generate energy. Some systems can do this, but the cost is much higher and with greater complexity than the mechanism created to heat water. The solar system that generates energy is known as a photovoltaic system.
9. Does this system harm the environment?
No way! Solar water heating is considered clean energy. It does not emit carbon dioxide (or CO²). To give you an idea, for every square meter of solar collector installed, flooding up to 112 square meters of water for hydroelectric power generation is avoided.
10. Is the maintenance of this system expensive?
Still thinking about enhancing the results obtained by this mechanism, it is recommended to clean the capture plates every six months to ensure greater efficiency in heating.
This cost is relatively low, and less compared to gas and electric heating systems. This correct maintenance makes it possible to keep this system in good condition for decades.
11. How is the water stored?
A traditional thermal system of this type of heating is composed of a solar collector and a solar thermal reservoir. This equipment is installed in the attic, little castle or other structure close to the roof, receives cold water through the water tank, and goes through the heating process, safely storing to be used when necessary.
12. How can I control the water temperature?
The mixing valves at the consumption points must control the water temperature. It is recommended to open the cold water valve first and then the hot water valve to avoid accidents with hot water. On a sunny day, when the temperature reaches 90ºC of the heated water, mixing the cold water with the hot water will make it easier for you to reach the shower at the ideal point for your shower.
There is also the possibility of installing temperature control valves at the tank outlet for the shower, as they pre-mix the water, allowing only water to pass for consumption at a temperature predetermined by the valve.
How the solar thermal reservoir works
One of the essential components of the solar heating system is the thermal reservoir. It is essential for storing and conserving hot water from solar collectors. Therefore, all attention is little before choosing the supplier of your solar heating system! To know what you should or should not consider when evaluating the equipment, I have listed the most common doubts of those looking for the equipment.
1. What is the solar thermal reservoir made of?
It consists of three essential parts:
Internal body – is the place where the water is effectively stored. It is in direct contact with water, so it must be made of corrosion-resistant materials such as copper and stainless steel. Because of the cost-effectiveness, the vast majority of manufacturers use stainless steel.
Thermal insulation – has the function of maintaining the temperature of the water that is inside the internal cylinder for a certain period. In the vast majority of equipment on the market, thermal insulation is made of expanded polyurethane.
External body – the purpose of the finish is to protect the thermal insulation from the weather. It is usually made of aluminum, galvanized steel or painted carbon steel.
2. Why do some thermal reservoirs have electrical resistance?
This mechanism acts as an auxiliary to contribute to water heating in periods of low insolation. Depending on the chosen reservoir model, this item can be standard or optional.
3. What are the differences between high and low-pressure tanks?
The low-pressure model is indicated when the cold water tank that feeds the storage unit has a difference of up to 4 meters about the base itself. The high-pressure tank is recommended when the water tank that supplies it is more than 4 meters in level in relation to the base. High-pressure equipment is also indicated when it makes up a pressurized water network, functioning as a motor pump.
4. What criteria should I take into account before choosing?
First of all, you need to check your daily demand for hot water. How much hot water do you need and at which distribution points at the installation site? This is important to define the size of the thermal reservoir you must acquire.
After all, there are models with capacity ranging from 200 to 5,000 liters of water. For this definition, look for the nearest dealer to help you with this calculation.
5. What precautions should I take when choosing a model?
Check the size of the chosen model, observing the height (considering the feet) and the length (taking into account the feeding tubes) of the equipment so that it fits in the place destined for it.
Check if it is necessary to reinforce the structure that will receive the reservoir, for example, the construction of bollards.
Check the correct working pressure for your installation, considering the reservoir models available for each situation as stated above;
Install the reservoir as close as possible to the points of consumption, preventing the water from cooling in the pipes (because it travels great distances) and, consequently, unnecessary water consumption.