ES2272171B1 - INSTALLATION OF HEATING AND HOT SANITARY WATER THROUGH SOLAR THERMAL ENERGY. - Google Patents

Abstract

Heating and sanitary hot water installation using solar thermal energy. Heating and sanitary hot water installation using solar thermal energy. It comprises a primary circuit with a solar collector system (1) with heat generator functions, through which a thermal fluid circulates, in series with the consumptions or heat exchangers (15) of a heating installation or sanitary hot water, and temperature limiting means, which prevent the temperature of the thermal fluid in the primary circuit from rising above a predetermined maximum temperature, and a safety circuit (2, 3, 4) with an expansion vessel (2), arranged in parallel with solar collectors. The temperature limiting means comprise a heat sink (10), arranged in parallel with the solar collectors (1) and in the same safety pipe (3) downstream of the expansion vessel (2).

Description

Heating and hot water installation Sanitary by solar thermal energy.

Technical sector of the invention

The present invention relates to a heating and domestic hot water installation by solar thermal energy, based on a solar collector system planes, through which a thermal fluid circulates and which are arranged in series of at least one collector in a field of flat solar collectors, which is in series with a heating or sanitary hot water installation, particularly, although not exclusively, of domestic type or residential. The installation includes limiting means of temperature.

Background of the invention

It is increasingly frequent that facilities Domestic hot water (DHW) and domestic heating thermally powered by flat solar collectors, with the consequent advantages of being able to dispense with the supply of fossil fuels, to improve overall energy efficiency and of being absolutely harmless from the point of view environmental.

Conventional flat solar collector systems usually comprise a field of collectors, associated in series and in parallel, in whose interior a liquid circulates, which can be water, which is heated by the effect of solar radiation. To improve performance, the collector liners are currently made of radiation-selective materials, which allow the passage of solar radiation in one direction and not in the opposite direction, so that all radiant energy passes into the liquid. The liquid, once heated, can circulate by natural convection or by pumping to the domestic installation, where its energy content is consumed in the installation of ACS, heating, pool conditioners or similar systems, cooling the liquid, and from where it returns , at a lower temperature, to the field of
collectors

The new European Standard EN12828 on systems of heating in buildings and design of heating systems by water, which is also applicable to ACS systems (water sanitary hot) dictates that the systems must be equipped with safety devices against maximum excess temperature of functioning. This standard is applicable to the systems of heating and ACS whose thermal generation system, or generator of heat, either by solar collectors.

The Standard indicates that when this temperature Maximum operating on the primary side of consumption is 105ºC, it is only necessary to have a temperature regulation of operation on the side of the secondary. However it would be optimal have means to ensure that the temperature in the primary does not exceed 105 ° C (except the obvious peaks by thermal inertia up to 115 ° C).

Standard EN 12828 proposes some examples of installation.

The present invention aims at provide a new heating and hot water installation sanitary by solar thermal energy with means temperature limiters that facilitate the achievement of these Security objectives in an easy, autonomous and efficient way.

Explanation of the invention.

To this end, the purpose of this invention is a heating and hot water installation sanitary by solar thermal energy, of new concept and functionality, of the type comprising a primary circuit with a solar collector system with generator functions of heat, through which a thermal fluid circulates, in series with the consumption or heat exchangers of an installation of heating or domestic hot water, and limiting means of the temperature, which prevent the temperature of the thermal fluid in the primary circuit rises above a maximum temperature default, and a safety circuit with an expansion vessel, arranged in parallel with the solar collectors, and that in its essence is characterized because said limiting means of temperature comprise a heat sink, arranged in parallel With solar collectors.

According to a first scheme according to the invention, the heat sink is arranged in the same pipe downstream safety of the expansion vessel; and why the stretch descending from said safety pipe extends to the return or entry of solar collectors through a valve retention.

In such a scheme, preferably, at the exit of the solar collectors (1) there is a temperature sensor 17 with switch, adapted for, when the water temperature at collector output reaches a preset temperature, send a stop signal to a circuit drive electric pump 16 primary, so that the fluid is recirculated to the circuit of security.

According to a second scheme or embodiment of the invention, the installation comprises a thermostatic valve built-in sensor at the output of the solar collectors, at the which pours the descending section of the safety pipe of the safety circuit and connected to a first end of the heatsink of heat; and a bypass pipe and a connection from the second end of the heat sink to the pipe expansion.

Preferably, the heat sink is a copper fin heat exchanger.

In the first scheme, to check valve It can be of the type claret, normally open

According to another feature of the invention, the expansion vessel is installed so that the fluid level is at a temperature not exceeding 2.5 m above the level more elevated solar collectors.

Those skilled in the art will appreciate that, thanks to the new and inventive features of this invention, the system object of it manages to solve the problems and inconvenience of the current technique exposed at the beginning. In addition, the solar collector system according to the invention does not requires permanent personal attention or additional facilities or additional electrical, does not require supplementary deposits, or devices with moving elements, such as pumps or fans. He additional fact that it does not require automatisms also collaborates in that Less breakdowns occur. In addition, it does not require electrical consumption supplementary, so, as experts in the technique, the overall energy efficiency increases with respect to current conventional solar collector systems.

Brief description of the drawings

The detailed description will be made below of the preferred embodiments of the present invention, for whose best understanding is accompanied by some drawings, given merely by way of non-limiting example, in which:

Fig. 1 is a scheme of principle and operation of a system with flat solar collectors Conventional according to EN 12828, with a primary circuit and a safety circuit with expansion vessel, applied to a DHW or heating consumption installation;

Fig. 2 is a scheme of principle and operation of a heating and hot water installation solar thermal energy according to the invention according to a first embodiment; Y

Fig. 3 is a scheme of principle and operation analogous to that of Fig. 2, corresponding to a Second practical embodiment of the present invention.

Detailed description of the drawings

In these drawings you can see the constitution and operating mode of the heating and hot water installation according to the invention, which complies with the Spanish standard and European UNE-EN 12828, where it is prohibited to overcome the temperature of 105ºC in the primary circuits of the heating and sanitary hot water installations and also prevents overheating in solar energy installations thermal

A schematic principle can be seen in Fig. 1 and operation of a system to flat solar collectors that responds to standard EN 12828, with a primary circuit and a safety circuit with expansion vessel, applied to a DHW or heating consumption installation. The indicated following numerical references:

one.

heat generator - battery solar collectors

2.

glass of expansion

3.

safety pipe

Four.

feed pipe and expansion

5.

tube overflow

6.

filling pipe

7.

water level limiter

8.

return pipe

The installation comprises a primary circuit with a solar collector system 1 with generator functions of heat, through which a thermal fluid circulates (usually water and antifreeze), in series with consumptions or exchangers  15 heat from a heating or hot water installation sanitary In this case, a heating installation is illustrated, in which the exchangers are radiators 15.

The installation is complemented, in a way itself known, with a safety circuit, arranged in parallel with the solar collectors and that has a feed pipe and expansion 3, an expansion vessel 2 and a safety pipe 3 with downpipe, In the drawings it can be seen that the expansion vessel 2 It is open to the atmosphere and is complemented by the pipe filling 6, overflow tube 5 and a water level limiter 7, for example buoy.

The installation is completed with some means temperature limiters, which prevent the temperature of the thermal fluid in the primary circuit increases above a maximum predetermined temperature, specifically 105 ° C - at which corresponds to a gauge height or pressure in excess of 0.25 bar - as ordered by the new European Standard EN12828.

As a novelty provided by the present invention, the temperature limiting means comprise a heat sink heat 10, arranged in parallel with the solar collectors 1, constituted for example a copper tube and fins thereof material, which will play the role of heat sink water-air or condenser vapor-air according to the cases.

According to a first variant of the invention, shown in Fig. 2, the heat exchanger or heat sink 10 is sandwiched in the same safety pipe 3 is sandwiched.

This safety pipe 3 is extended according to the descending section 11 to the return or input 8 'of the battery manifolds 1 and at its final end a valve is installed retention 9, preferably of the light clapper type (density less than 1.1 kg / dm 3) and normally open.

The expansion vessel is installed at a height not greater than 2.5 m counted from the top of the collectors

According to this provision, the pressure of the 16 primary circuit drive electric pump will keep closed the check valve 9 and the heat transfer fluid (generally water and antifreeze, circulate exclusively to through the battery of collectors 1 and its operation will be the normal.

In such a scheme, at the exit of the collectors solar 1 there is a temperature sensor 17 with switch, adapted for when the water temperature at the outlet of the collectors reaches a preset temperature, send a stop signal to a primary pump 16 of the primary circuit, so that the fluid is recycled to the safety circuit.

Thus, when the heat transfer fluid of the primary circuit reaches the set limit temperature, the operation of the pump 16 will be stopped by the corresponding electrical interlocking. The check valve 9, without the action of the pressure, will remain in the open position and a gravity circulation (thermosiphon) will be generated in the outlet direction of manifolds 1 → exchanger 10 → down pipe 11 → check valve 9 → 8 'input to collectors
one.

This gravity circulation will cool automatically any system overheating through of heat exchanger 10 depending on heatsink air Water.

In this way, in no case at all the temperature may be higher than 105 ° C, as established by the standard, since even in the most unfavorable circumstances (temperature extraordinarily high exterior and reduced surface area of exchanger 10, at a pressure of 0.25 bar (gauge height of expansion vessel 2 to 2.50 m) corresponds to that temperature of 105 ° C vaporization.

In the limit, high steam temperature makes that the exchanger 10 increases its transmission power of heat and, now in condenser function, condense the steam. Water condensed down the downspout 11, the check valve 9 and again will return to collectors 1.

The check valve 9 of Fig. 2 can be of any known type, for example ball or clapper. It has been thought that, preferably, the density of the sealing element of this valve 9, ie the clapper or the valve is somewhat lower to water density, for example 10% lower so that, of this way, to be able to hinder the circulation of water to small thermal jumps, for example when the system starts up.

Optionally, according to another variant, represented in Fig. 3, a mechanical thermostatic valve 12 can be installed built-in sensor, a bypass tube 13 and a connection 14, instead of the previous downpipe 11 and the valve retention 9 of Fig. 2.

This scheme in Fig. 3 perfects the anterior of Fig. 2 at the following two ends:

1) in normal operation, valve 12 closed interrupts any kind of vagrant currents in upward direction, solar collector pass-exchanger 10 which could cool the primary circuit slightly.

2) modulate the cooling with the pump of the installation in progress: if thermostatic valve 12 has adjusted opening at 90 ° C, for example, when opening the communication step with exchanger 10, the electric pump 16 of the installation drives the fluid in parallel through the solar collectors 1, and also by exchanger 10, keeping the system below of the temperature of 90 ° C.

Under operating conditions with pump 16 stop, a gravity circulation (thermosiphon) is established, one way of manifolds 1 → valve 12 → return to collectors 1 by bypass 13 \ return return to collectors 1. This circulation carries at all times the higher temperature of the manifold fluid to the sensor of the valve 12, which will "open" at its setpoint temperature and establish gravity circulation similar to the previous scheme of Fig. 2.

Thanks to its great simplicity, the system of invention is very low cost, both in investment and in maintenance and offers total reliability.

Those skilled in the art will understand that installation of the present invention allows to obtain important technical-functional and economic advantages. From Among the technical-functional advantages, highlight the following:

a) avoid the usual and inconvenient overheating in summer of this kind of facilities with its innumerable negative consequences, such as:

- oversized closed expansion vessels and loss of water and antifreeze;

- degradation of the selective surfaces of the collectors;

- discomforts in manually covering the solar collector surfaces;

- installation of supplementary deposits; electric pumps and electric fans with their corresponding dependence and consumption of electricity supply;

- formation of scale and corrosion; pump cavitation; etc.

b) the system fully complies with the temperature limitation of the Spanish and European standards UNE-EN 12828, without relying on any kind of electro-automatisms, nor of the power supply electric

The main economic advantages of the present invention are

a) this system eliminates the direct cost of all class of automatic and manual air and gas traps and Large closed expansion tanks.

b) the system supports, like any installation domestic plumbing, welding pipes and fittings copper by capillarity (tin-silver) instead of silver solder of very high price both in material of contribution as in its execution by qualified personnel.

c) minimum maintenance cost, limited to Simple supervisions

Claims (7)

1. Installation of heating and sanitary hot water by means of solar thermal energy, which comprises a primary circuit with a system of solar collectors (1) with functions of heat generator, through which a thermal fluid circulates, in series with the consumptions or exchangers (15) of heat of a heating or sanitary hot water installation, and temperature limiting means, which prevent the temperature of the thermal fluid in the primary circuit from rising above a predetermined maximum temperature, and a safety circuit ( 2, 3, 4) with an expansion vessel (2), arranged in parallel with the solar collectors, characterized in that said temperature limiting means comprise a heat sink (10), arranged in parallel with the solar collectors (1). 2. Heating and sanitary hot water installation by means of solar thermal energy, according to claim 1, characterized in that said heat sink (10) is arranged in the same safety pipe (3) downstream of the expansion vessel (2); and because the descending section (11) of said safety pipe extends to the return or inlet (8 ') of the solar collectors (1) through a check valve (9). 3. Heating and sanitary hot water installation by means of solar thermal energy, according to claim 1 or 2, characterized in that it comprises, at the exit of the solar collectors (1), a temperature sensor (17) with switch, adapted for, when The temperature of the water at the outlet of the collectors reaches a preset temperature, sending a stop signal to an electric pump (16) of the primary circuit drive. 4. Heating and sanitary hot water installation using solar thermal energy, according to claim 1, characterized in that it comprises a thermostatic sensor valve (12) incorporated at the outlet of the solar collectors (1), to which the descending section of the safety pipe (3) of the safety circuit and connected to a first end of the heat sink (10); and a bypass pipe (13) and a connection (14) from the second end of the heat sink to the expansion pipe (4). 5. Installation of heating and sanitary hot water by means of solar thermal energy, according to any one of the preceding claims, characterized in that the heat sink is a heat exchanger (10) of copper fins. 6. Installation of heating and sanitary hot water by means of solar thermal energy, according to claim 2 or 3, characterized in that the check valve (9) is of the key type, normally open. 7. Heating and sanitary hot water installation using solar thermal energy, according to any one of the preceding claims, characterized in that the expansion vessel (2) is installed so that the fluid level is at a temperature not exceeding 2.5 m above the highest level of solar collectors (1).