A water heater or heater washed, water heater, or boiler is a device thermodynamic using energy to raise the temperature of the water.
Among domestic and commercial uses of hot water are cleaning, showers, cooking or heating.
On an industrial level, the users are very varied for both hot water and water vapor.
Among the fuels used are natural gas, propane gas (LPG), kerosene and coal, although electricity, solar energy, heat pumps (compressor) from refrigerators or air conditioners, recycled heat are increasingly used of wastewater and even geothermal energy.
In the case of water heated with an alternative or recycled energy, these are usually combined with traditional energies.
Types of water heaters:
The best-known types of water heaters are:
- Spot heater
- Boiler heater
- Solar heater
- Accumulation heater
- Boiler (for recirculation).
The heater type and fuel type selected depends on many factors such as the temperature of the water to be achieved, local availability of fuel, cost of maintenance, cost of fuel, usable physical space required flow instantaneous, local weather, and heater cost.
Point heaters, instantaneous step or flow:
These heaters are very small units installed a short distance from the place where hot water is required.
They are powered by electricity and activated automatically by flow or manually with a switch.
Its use is reduced to a few commercial or domestic applications.
They have a reduced power consumption ranging from 1500 W to 5000 W. They only have a practical use in temperate countries, given their low heating capacity.
We can find examples of its use installed directly to washbasins or showers (showers) knitted, common in affordable homes in temperate countries.
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Also called instantaneous heaters or flow heaters they are also small in electric models and somewhat larger in natural gas or LPG models.
They are units that are turned off, without consuming energy, a flow sensor is activated when they detect water circulation and start their healing procedure.
The electric models range from 8 kW.
Gas models can reach 31.4 kW (8 kcal / s) as is the case of a heater of 18 L / min.
The electric models are equipped with immersion heating resistors and the gas ones light a flame that heats a heat exchanger where water circulates.
The most advanced models are equipped with electronic temperature controls and flow meters.
In this way, the user can select the desired temperature in degrees.
The electronic controller measures the flow of water that is circulating, the inlet temperature, and adjusts the power that the heating resistors will apply in the case of electric models or the size of the flame in gas models.
Electric models can apply 99% of the energy consumed to water, while gas models reach between 80% and 90% efficiency. In the case of gas heaters, unused energy is released in the form of hot gases.
The electric models can be installed in closed places because they do not require ventilation, instead.
Operation of the gas heater:
Gas heaters are equipped with a vitrified steel boiler and an internal heat exchanger element.
The gas combustion chamber and the burner are located at the base of this duct.
The combustion safety in pilot flame models is guaranteed by the existence of a thermocouple, which in case of ignition of the flame prevents the passage of gas to the burner, but the gas continues to reach the burner continuously so that the service is always ready.
The overheating thermostat is an additional safety measure, preventing the water temperature from exceeding 95 · C.
The great advantage of the gas thermos is given by:
The accumulation, which allows providing hot water service to several points of consumption simultaneously (unlike instantaneous production systems).
Its great heating power, capable of recovering the water temperature more quickly.
In the long run, the highest cost associated with water heating is fuel, rather than the cost of the equipment and its installation.
We pay the water heater and its installation only once, while with the fuel we do it every month.
Boilers are undoubtedly the most efficient systems for heating and providing hot water, maintaining a constant temperature regardless of use.
A well-balanced boiler system can provide hot water for heating and for direct use simultaneously.
The boilers provide steam for commercial and industrial uses safely and efficiently.
There are several types of boilers but in their basic concept, they are metal containers
(copper, stainless steel or cast iron) through which the water circulates.
This container is crossed by hot bars. The fuel to heat these bars can be gas, fossil fuel, wood, nuclear fission or even heating resistors if it is electric.
Water circulates, in some cases through a water pump through pipes that run through places where hot water or steam is required.
Unused water returns to the boiler to restart the cycle.
A level system measures the missing water and adds it if necessary.
For homes, only the use of boilers is justified in countries with climates with four very marked.
Natural gas is the most economical, is the logical option in most countries. In this respect, in certain countries and for certain users, the so-called “minimums” (power quotas, rental of facilities, periodic reviews …) must be taken into account.
The proportion of the invoice that these “minimums” represent, From an exclusively economic point of view, this logical option can be discarded in some cases.
In addition, natural gas is not always available, especially in remote areas.
The second option is propane gas or LPG.
It is part of us to do research work to know what fuels are available in the area and which offer better savings options.
more regularly than cold water. Preventive maintenance is associated with water softeners or softeners.
Tank heaters or boilers additionally require the emptying and cleaning of the tanks to extract the accumulated sediments inside.
The frequency of this cleaning depends on the number of solids contained in the water we heat.
Tank heaters made of galvanized iron tend to oxidize and corrode.
To avoid this and extend the life of the tanks, some equipment has a sacrificial anode of magnesium or aluminum. The status of this anode should be reviewed as part of annual maintenance.
In the case of gas heaters, cleaning and overhaul of the heat exchanger are recommended once a year. Impurities from natural gas can clog the radiator.
The review of security systems by specialized personnel must be included in the maintenance of the
Pressure relief valve:
Although heating water we see it as a normal process and nothing dangerous, it really is.
The water after passing 100 ° C becomes steam when it passes from the liquid to the gaseous state it expands and requires more space by increasing the pressure of the container where it is contained.
Safety thermostat with manual reset. If water is heated inside a tightly sealed container, when the water exceeds 100 ° C, it will burst.
Although under normal conditions it is very difficult for a water heater to burst, it is a fact that has happened before.
To avoid this, the heaters have a temperature control system and a safety system.
The control system consists of a thermostat that turns the heater off and on at certain water temperatures.
The most advanced systems have an electronic control system, instead of the thermostat, which regulates the power applied to the water.
The safety system consists of a pressure relief valve and a second thermostat in some cases.
The relief valve releases the pressure allowing water or steam to leave the tank if the internal.
In heaters with a second safety thermostat, it is graduated to trigger at a temperature higher than the control thermostat.
In this way if the control thermostat fails, the safety thermostat will trip to prevent the temperature from rising above 100 ° C.
Once the safety thermostat is tripped, the heater will not work again until it is manually reset, this way the control thermostat will have to be repaired or replaced.