# Facilities of Heating in the houses

In this subject we are going to try how to create a comfortable atmosphere in our houses, whereas clause the energy source and the form to transmit the heat. As energy sources we have as more used, the natural gas, gas propane, diesel oil, the electricity and lately pellet (within the green energies). As forms to transmit the heat we have the water radiator, hot air systems (pellet or firewood), systems of natural radiation by direct combustion as the case of the chimney, radiating ground, etc.  In the image of the right we showed a simple installation of radiators fed by water, that is warmed up by a gas boiler. The circuit is simple. It consists of a line of hot water that is warmed up by the boiler happening to each radiator, which they warm up and they radiate calorific energy (of there the name of radiators). The water to its exit happens to the cold circuit of water to again return to be warmed up in the boiler.

## Important aspects of the radiators

1 the radiators usually are made of aluminum and have an entrance with a regulating key and an exit, where a holder is put (to see image) to regulate the water flow.

2 Although the key and the holder serve to let pass the water, the function is different. If a dormitory reaches the temperature in a moment and we do not have key with thermostat, we are going to pass heat, reason why we closed a little the key. Tomorrow it can be more cold and I want that This is warmed up soon (I open the key to the maximum) can also be done with the holder but the function that it has is another one. If we phelp attention to the installation of radiators of above we observed that there are two closely together of the exit of the boiler but another one but far, with a hot water pipe but it releases, that is losing heat throughout the passage. It is logical to think that at the near radiator him C can arrive the 68 water to 80 and to but the distant one to C. This is translated more in less heat for the moved away radiator. Aside from the temperature of the water, the water that is going to happen through the nearest radiator would be greater. How we solved it. Simple, if I make pass less water through the near radiator and but by the distant one I have both emit the same heat and that, it is only made once in the process of the installation by means of the regulation of the holders.

3 the white radiators are a shoddy work€ from the point of view of efficiency energetics. Thus he is, very beautiful but little efficient. It is possible to be demonstrated that a black radiator emits more energy than one target. The dark colors are hardly used that are but effective by aesthetic.

4 By the law of Stefan-Boltzmann, for a hot ideal (black body) the broadcast energy depends on the temperature of the water lifted to fourth multiplied by the constant sigma Ïƒ   , this is:

Broadcast heat = Ïƒ x t4

I feel Ïƒ a coefficient. Therefore, he is but interesting to have the radiator to lifted temperatures to have better yield.

5 the circuit of water usually contains air that is accumulated in the high part of the same lowering its yield. For it the purgadores settle (automatic manuals or) that allow the exit of the air. To the left we have one automatic one. In the Institute, every year they must bleed the installation because the radiators have purgadores manuals. An installation that contains air usually is annoying by the noises that originate.

6 the face of the radiator that it gives to the wall is little effective then most of the broadcast heat is lost in warming up the wall and of there to the outside. In order to avoid it, he is advisable to put some special insulating cloth that in addition reflects the radiation to the interior of the room.

In the market they exist this special lamina type who, as he is in the figure, has a spongy layer (insulating) and a metallic one (to reflect to you).

## Control of the Temperature.

The radiators can have a key manual to control the passage of water and this form to control the temperature, or with automatic keys even some programmable ones, that activate the water passage according to the fit hour and the programmed temperature. An example we have it in the image of the left. These keys usually are very expensive. Independent of this keys, all installation must have the corresponding thermostat that once deactivates the boiler reached the temperature. Usually they are electronic and programmable so that they adjust for an hour strip and to a certain temperature.

We enclose of basic form the electronic scheme of a thermostat. The black block is a comparator that compares entrance 2 seizure of the potentiometer that selects the temperature and the 1 that takes the tension from the resistance-blue-Termoresistencia splitter.

If the low temperature, the value of the low tension and the comparator activate making work to the relay and this the element heating engineer (boiler, resistance. ). The termoresistencia can be a NTC or a PTC, according to the type of thermostat.

## Heat systems

How we warmed up the water. One of most basic is the liquefied gas (GLP or Liquefied Gases of Petroleum)   as they are the butane or propane.

If we had, that is to say, to transport the gas in its normal state as gas, the package would be enormous and for that reason it is necessary to compress to reduce the volume, and when doing it, the gas happens to the liquid state as it is appraised in the figure and it is stored generally in packages, of steel.  When the valve is opened, the regulator again passes the butane (or propane) liquid to used gas for.

If we admitted that the butane behaves as an ideal gas, the formula that defines its behavior is:

P * V = n *R * T

Where:

•  is the Pressure of the Gas
•  the volume that occupies
•  the number of masses (something as amount of matter of the gas)
•  R is one states < title=€ Constant universal of ideal gases€ >
•  Measured T is the temperature in K.
`If we maintain the Temperature and as n and R are equal, when lowering the volume of the gas, the pressure raises and brings about the liquification.`

Unlike the natural gas, the gas butane is denser than the air. This implies that a gas escape, brings about an accumulation of gas in the ground.

More times of the desirable ones and while we took a shower, we remained without hot water. We put the bathrobe and we go to the gas thermus. We see that one has gone out, we ignite a match to ignite the thermus and soon we threw it to the ground. If there were a gas escape we have assured the shaving the legs, and this is not a joke.

In order to avoid this, where we have the gas bottle must have a vent (exit to the outside) in the low part of the wall

## Boilers

In the image we have a very basic representation of how it would be a gas boiler on the inside, with the following components:

• Cold water pipe (Cold to water in) that enters the boiler again from the radiators to be warmed up in the heat exchanger (Heat Exchanger), that is not another thing that a metallic block that is warmed up by the burner.
• Hot water pipe (Hot Water Out). Once the pipe gives returns in the interchanger, the water is warmed up and it is given to this hot water pipe, that will be the exit. To see as in the interchanger the increase of the temperature of the water imagines from blue, white, yellow and red according to the water is taking temperature.
• Water sensor (Sensorial Flow). So that the boiler works, it is necessary that water enters because, otherwise, gas for anything would be burned and in addition could reach very high temperatures. If water flow is not detected, the machine does not work.  All this is controlled by the electronic place (green plate arrives at the left in the boiler)
• Burner (Burner) is where burning fire the gas next to the air that enters thanks to the ventilator (Fan)
• Water pump. Although not represented in the boiler, it is located to the entrance of the cold water and allows that the water circulates around all the circuit.
• Another series to components as temperature sensors, that avoid overheat, pneumatic pressure switches of air exists in addition, gas regulators, etc. In the part inferior of the subject, we represented a boiler but it completes with the components of the same

## ELECTRICAL HEATING

We can use electricity to warm up the house if we contracted night rate. In this tariff, in nocturnal hours the electricity has a discount of 50% on the daily one and understands from of the 22 to 12h in winter. The prices and hours can vary but not the concept to which we go.

It is evident that we are not going to at night pass cold until the 10 and therefore we needed some radiating that consume at night and give heat by the day. These radiators are called storage cells and they are not but that a system of special stone blocks which resistance are warmed up at night by means of some and for the day stops warming up to activate a ventilator that removes€ the accumulated heat at night to us.

We can emphasize as advantage that the heat is but economic, does not require very complicated installation little and but. As disadvantage, the size is greater to the one of a water radiator, with worse aesthetic, requires a reinforced electrical system in the house and is something noisier. Usually they are not used due to the extension of the canalized gas network that there is in the cities.

We have another called heat type blue heat€ that their manufacturers say who to the blue being are but economic. Pile of lies goes.

To consider that if we bought a blue heat radiator, green or garnet, if it has 1000 W will give the heat us corresponding to 1000W.

The only heat system that it gives but heat that the one that consumes is the heat pump (the one of air conditioning) and this are because by the cycle of changes of state of the gas that uses taking€ heat of the outside of the house for putting it€ within the house. In these cases, we can consume 1000 4000 W and generate 3000 or W, according to several factors.

Activities:

1. It explains the function that has the holder
2. The radiators sound, That we can make to solve the problem?
3. How be regulated the individual can temperature of a dormitory in a system of central heating?
4. It explains the function of the heat exchanger of a boiler. The explanation with a drawing helps
5. It explains that it is the radiating ground.
6. An electrical heating engineer has a power of 1000 W. What is the maximum heat that can give.
7. In the completion of an installation of heating by water,  that aspects you must consider.
8. The storage heaters keep the heat at night thanks to ................
9. The butane bottles have most of combustible in liquid form. Explain it with the formula of ideal gases
10.  In the thermostat, the element that is sensible to the variation of the temperature is called ....................

In order to know but:

## Components of a boiler

Entrance for the outer air. To the being the internal tube, is warmed up by the exit of hot air

1. Exit of the burned gases, that warm up to the clean air that enters
2. The air Pneumatic pressure switch when coming out verifies that it leaves the air.
3. Heat exchanger. The water pipes are calendadas by the flames of the burner
4. The Electrode of ignition activates the boiler whenever hot water is asked for
5. The Burner is a set of exit of gas, ordered to warm up the interchanger
6. Water pump for the heating
7. 2 Interchanging for hot water (water-water). In this model of boiler (not in all) we have the water that leaves the first interchanger warms up this one so that as well, it warms up the sanitary circuit of hot water
8. Safety valve
9. Sensor of water flow
10. Key to fill the circuit of heating
11. Key to drain the circuit of heating
12. Water cold entrance of the circuit of heating
13. Cold water entrance sanitary
14. Gas entrance
15. Sanitary exit of hot water
16. Exit of hot water of the heating
17. Concentric tube for the exit of gases
18. Ventilator for exit of gases
19. Glass of hot water expansion.  It is used to absorb to the increase of volume produced by the water the warmed up being
20. Thermostat of security for control of the temperature of heating
21. Sounding of temperature of the heating. The information is sent to the control plate
22. Electrode for the detection of flame. If it does not detect flame, one becomes to activate the ignition electrode. If after several attempts, it does not detect flame, it puts the boiler in way repair (way error) and it does not return it to try.
23. Valve of entrance of the gas
24. Sounding of temperature for the sanitary hot water
25. Pressure gauge for measurement of pressure of the hot water
26. Valve 3 routes. Whose purpose is a motorised valve is to direccionar the hot water volume coming from interchanger 1 (called interchanging water-gas), or towards the circuit of the radiators or towards the other interchanger for the sanitary hot water. If we did not open the faucet, the water goes to the radiators. If we opened the faucet, the water happens directly to the interchanging water-water to warm up the sanitary hot water. When coming out from this one interchanger, it returns to the interchanging water-gas.
27. Hydraulic pneumatic pressure switch. The pneumatic pressure switch (well-known as interrupting of pressure) is in charge to close the circuit of hot water following the reading of the pressure gauge.
28. External housing of the boiler