ES2338086A1 - VERSATILE THERMAL SOLAR SYSTEM OF HOT WATER PRODUCTION UNTIL HIGH TEMPERATURE. - Google Patents

Abstract

This concerns a versatile thermal solar system for producing hot water up to high temperatures. Thermal solar installation, comprising a battery (1) of two or more flat or vacuum-tube solar collectors (2), heat-transfer-fluid circulation pump (4), valve system (3) and control system (6), characterized by its wide operating range in terms of available temperature of the heat-transfer fluid (from +40 DEG C to +150 DEG C), also ensuring a constant flow of heat-transfer fluid, a constant temperature, or both parameters simultaneously. The control system (6) will act on the valve system (3), as well as on the speed of the circulation pump (4) to provide control over said parameters. All of the components of the installation shall comply with the standards required to withstand temperatures up to 180 DEG C.

Description

Versatile solar thermal production system hot water up to high temperature.

Technology sector

The present invention is part of the sector of renewable energy, specifically in the use of solar thermal energy for hot water generation in industrial installations, heating installations, absorption air conditioning and domestic hot water.

Making the appropriate changes of configuration and arrangement of the different elements of the solar thermal installation, great versatility is achieved in its operation, being able to obtain a heat transfer fluid to the required temperature in the consumption circuit, whether it is of average temperatures (+40, + 80ºC), as of high temperatures (greater than + 80ºC to + 150ºC), getting in the circuit primary, circuit through which the heat transfer fluid flows, some stable and continuous conditions in terms of temperature, flow, or both parameters simultaneously. Total control of all the parameters, being able to be used this type of installations for any use that requires thermal energy in a wide range of working temperatures (from + 40ºC to + 150ºC). These facilities may be executed by companies that have such technology.

So overheating is achieved in the installation is not a problem for it, as it happens currently, being able to work at lower temperatures and usual.

Thus, a work system is achieved at low and high temperatures (from + 40ºC to + 150ºC) stably and automatic, which allows a new and extensive field of use of solar energy.

State of the art

The Technical Building Code, in the HE4 section of HE Basic Document, defines a solar installation thermal like that which is constituted by a set of components responsible for capturing solar radiation, transforming it directly in thermal energy by transferring it to a working fluid and, finally, store said thermal energy efficiently, well in the same working fluid of the collectors, or transfer it to another, to be able to use it later at the points of consumption. This system is complemented by a thermal energy production by conventional auxiliary system that may or may not be integrated within the same facility.

A conventional solar thermal installation is composed of the following elements:

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A collection system, consisting of a battery of solar collectors, which may have a variable arrangement, associated with a pipe system, forming a circuit called a whole primary. Inside the pipes and manifolds a primary fluid circulates, usually water with the addition of a antifreeze, which will be responsible for capturing the energy that They have absorbed the solar collectors. For better performance of The installation, the solar collectors are coated with selective materials that allow the passage of radiation in a sense, but not in the opposite direction.

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A accumulation system, consisting of one or several deposits of accumulation of energy The energy captured from the solar radiation for use in the consumption circuit. It allows the use of energy at a different time than its catchment.

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A exchange system, where the energy is transferred from the accumulation system to a secondary fluid, which may be employed directly at points of consumption or it can be stored as hot fluid, for storage of the Energy.

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A system of consumption, formed by all the points of consumption of the installation, which, together with the exchange system, make up a second circuit called secondary circuit.

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A regulation and control system, by which the operation of the entire system, establishing parameters of slogan indicating the limits of proper operation, both primary and secondary circuit.

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A auxiliary power system, to supply the energy in the moments in which the energy coming from the solar circuit is not enough to meet the needs at the points of consumption.

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A fluid pumping system, which is responsible for causing the forced circulation of the fluid (both in the primary circuit and in the secondary) that runs through the pipes. Said system of pumping can be eliminated in cases of convection circulation natural, where difference between existing dimensions is used between the different elements of the installation.

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A safety system to avoid excessive overheating of the Solar system.

The energy captured from the solar installation will be transmitted to the secondary fluid thus generating hot water.

According to the European standard UNE-EN 12828 on heating systems in buildings and design of water heating systems, which is also applicable to ACS (domestic hot water) systems prohibit reaching in the primary circuit primary fluid temperatures greater than 105ºC, for the problems described, with which the novelty contributed by the present invention opens the field of use of solar thermal installations, in a temperature range of use of + 40ºC to + 150ºC, with absolute control of the fluid temperature, flow rate, or both parameters simultaneously, guaranteeing continuity of these parameters in the ranges of temperature indicated above. The invention is optimal application in industrial facilities that require hot water at high temperature, its greatest application being cold production by absorption, among others. However, considering security available to the present invention, it would be perfectly valid and safe for application in ACS installations (hot water sanitary), heating, air conditioning or other applications.

The primary fluid, which has yielded all or part from its energy to the secondary fluid, in the heat exchanger, returns to the collector field, where it will be heated again. From in the same way, the secondary fluid, which has yielded energy in the consumption points, return to the heat exchanger, where heats thanks to the presence of hot primary fluid.

Examples of solar thermal installations Conventional ones are described in patent documents with No. of publication ES497078 and No. 2156837, among others. In said inventions, temperatures at which they can work are not treated these facilities, nor the available flows.

An important factor to consider in the solar thermal installations is the need to have a security system that serves as protection against system overheating, freezing risks ... For the protection against freezing risks, water is usually used mixed with antifreeze so that the resulting mixture has a specific heat exceeding 3 KJ / KgK at 5ºC below the minimum historical temperature recorded in the area where it is located installation. In the case of overheating protection of the system, the installation will be equipped with safety devices manual or automatic to prevent overheating of the installation that may damage materials or equipment and that penalize the quality of the energy supply. Example of these devices are an adequate expansion system and a system of drainage to the outside of superheated fluid.

In the patent document with publication No.  2272171 proposes a new security system for solar thermal installations for water production for heating or domestic hot water, which prevents the fluid Primary exceeds the limit value of 105ºC. Similarly, the Patent documents with publication No. 2224844 and 2272174 describe a heat energy dissipation system in solar installations

Another of the very important aspects dealt with in solar thermal installations is the need in many applications reach a high operating temperature, in around 100ºC or higher. Analyzing the state of the art, to reach said temperatures in the heat transfer fluid of the primary circuit, the vast majority of the technology developed is focuses on the development of energy capture systems solar, either through solar energy concentrating systems, or other specially manufactured solar collectors. An example is described in patent document No. CN1461927, in which develops a solar installation using a collector system Specially manufactured, which ensures a rapid reach of high operating temperatures In the patent document No. ES2035990 refers to a solar collector for the high temperature generation.

In other cases, as explained in the invention with No. US4021895, special facilities are developed. In bliss invention, different batteries or groups of collectors are arranged, each of which works at different working temperatures, delivering the heated heat transfer fluid to different tanks of storage, or to the same stratified tank. To do this, it feature collectors are required in each battery special.

It would therefore be desirable that solar thermal installations were equipped with a system that allowed them to generate water at elevated temperatures (more than 100ºC), without using special collectors or solar concentrators in large fields, being also facilities versatile enough to generate water to lower temperature without changing Materials in the original installation. With our system of regulation and control that acts on those parts of the system that affect the disposal of batteries or collector groups solar, or the amount of heat transfer fluid circulating at through these batteries.

Patent documents with No. JP56068753, US4474169, JP57157958, DE102005008646, among others, describe inventions of solar installations that reach a high operating temperature, without specifying the temperature range Possible work. All these inventions are based on the use of an adequate valve system, which allows changing the configuration of the battery of collectors, arranging them in series, when you want to raise the temperature of the fluid heat carrier, or in parallel, when the temperature is to be maintained or reduce With this system you can regulate the temperature at collector battery output, but not maintaining a constant flow in the solar installation. In addition, the possible temperature variations at the outlet of the collector battery They seem high. Another feature to highlight here inventions is the absence of information regarding collectors necessary solar in them, not indicating if it is needed have special or commercial solar collectors currently existing in the market are valid.

Other inventions, as indicated in the Patent documents with No. US4257395 and US4130110, allow regulate the temperature of the heat transfer fluid thanks to a system of regulation and control that acts on the pump motor primary circuit circulation, to vary the flow that runs through said circuit. Although it is allowed to regulate the temperature, the flow rate is not constant.

The state of the art mentioned above, presents facilities that allow temperature control in solar thermal installations, without ensuring correct operation of them at high temperatures. I do not know ensures a constant flow, or constant temperatures of utilization, or both parameters simultaneously.

The present invention, by means of a suitable control and regulation system, focuses on characterizing a installation of solar thermal energy collection of a versatility such that it allows the generation of water or other fluids over a wide range of temperatures (from + 40ºC to + 150ºC), with total security, without using special collectors or solar concentrators, starting from a minimum of two units in ahead. This versatility is obtained by maintaining some contributions constants of heat transfer fluid to the secondary circuit in terms of temperature, flow, or both parameters simultaneously.

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Description of the invention

According to the state of the art existing until the At the moment, the present invention aims to solve the multiple problems arising in solar thermal installations when reach high temperatures in the primary circuit (greater than 100 ° C). Really, in many cases, solar installations currently existing thermal do not allow to reach this range of high temperatures, on the contrary, in its design they are contemplated safety systems that avoid temperatures greater than 105ºC.

It is intended to develop a solar installation thermal versatile enough to work correctly at low and high temperatures, depending on the necessary temperature in the secondary or consumption fluid, making the most of all the energy received throughout the year, for application in industrial facilities, being of great utility to produce domestic hot water, water for heating, air conditioning or refrigeration facilities by absorption, etc.

The current state of the art contemplates solar thermal installations that reach high temperatures in the primary fluid, in which the installation of concentrating devices of solar energy or other systems collection specials. In other cases, it is possible to increase the fluid temperature, but does not remain constant throughout the weather. In the same way, other examples of inventions cause variations in the flow to reach said high temperatures. The present invention aims to reach these elevated temperatures (up to 150ºC in the primary circuit), using as a means of solar collection solar collectors (2) flat or vacuum tubes conventional, also ensuring temperatures and flow rates constants in the primary circuit.

To achieve the objective of this invention, a solar thermal system is designed, whose peculiarities they are in an adequate control and regulation system (6). Said control and regulation system (6), allows, depending on the temperatures and flow rates required in consumption, act in the primary circuit in two aspects fundamentally: on the one hand, the flow driven by the circuit pump can be controlled primary (4), varying the speed of its engine; on the other hand, it the configuration and arrangement of the battery (1) of solar collectors (2), to ensure an outlet temperature of The right collector battery.

Another feature of the present invention is that all components of the solar thermal installation will comply with the necessary standards to work correctly with Heat transfer fluid temperatures up to + 180 ° C.

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Description of the drawings

A scheme of principle of solar thermal installation object of this invention.

Figure 1 shows a battery of solar collectors (1), consisting of two or more solar collectors (2), no limit of units. These will always be solar collectors flat or vacuum tube, but devices will never be used solar radiation concentrators or other type of solar collector special. Through a 3-way valve system (4), it is allowed have one configuration or another in the field of collectors, depending on the needs, in the primary circuit. A circulation pump (4) It is responsible for moving the heat transfer fluid that circulates through the collector battery (1).

The energy captured in this primary circuit is transported by the heat transfer fluid and transferred to a circuit of consumption or stored in water tanks using exchangers of heat (5).

For system regulation, there is a temperature probe (9) at the outlet of the collector battery (1) and temperature probes (10) at the exit of each of the solar collectors (2).

Through a regulation and control system (6) it acts on the different elements of the installation to Reach the objective needs.

The primary circuit of the solar system closes with a discharge pipe (7) of the heat transfer fluid, which enter all solar collectors (2) and a return pipe (8), which collects the heat transfer fluid and directs it to consumption.

Figure 1 shows probes of temperature, air traps, stop valves and valves retention, expansion systems, etc., elements all of them typical of a solar thermal installation.

The solar collectors used in the installation are conventional existing in an installation solar thermal, using flat solar collectors or tubes empty. The rest of the material used will comply with the standards necessary to work correctly with temperatures of up to 180 ° C.

Detailed description of the invention

Be part of a solar thermal installation conventional, to which the appropriate changes will be made to achieve adequate versatility in its operation, as well as reach high and low operating temperatures, according to the needs

It has a battery (1) of collectors solar (2), being these in number of two or more units, the which will always be flat solar collectors or vacuum tubes, never solar concentration system or other type of solar collector special. Through a circulation pump (4) fluid is sent heat carrier through the discharge pipe (7) towards the collector battery (1). The solar collectors (2) will be the responsible for transferring energy from the sun to the fluid heat carrier The fluid is sent through a return pipe (8) heated heater to the consumption circuit using for energy transfer one or more heat exchangers (5).

A control system (6) will be responsible for regulate the installation in its entirety. To do this, it will act:

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On the 3-way valve system (3) of the manifold battery (1), to change its configuration, arranging the solar collectors (2) with one configuration or another, depending on the temperature and / or flow required in the circuit consumption.

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On the circulation pump (4), which will be responsible for regulating the flow that will circulate through the collector battery (1), depending on of the necessary flow.

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On the rest of the components of the installation in its secondary circuit (not developed in the present invention).

The rest of the installation elements are conventional (safety valves, non-return valves, filters, temperature probes, pressure gauges, thermometers ...).

The system can work to reach a setpoint temperature at the heat transfer fluid outlet, for move a setpoint flow in the primary circuit, or both parameters simultaneously.

In case you want to reach only one setpoint temperature at the outlet of the collector battery (1), the system starts operation by starting the pump circulation (4) with a necessary initial flow. The fluid heat carrier circulates through the primary circuit and enters the battery of manifolds (1) by means of the discharge pipe (7), which supplies to all solar collectors (2). The valve system (3), is initially arranged in such a way that the collectors (2) have a initial setup. The heat transfer fluid is heated by the solar collectors (2) so that when any of the probes (10) placed at the exit of each solar collector (2) mark the setpoint temperature, the valve system (3) changes the configuration of solar collectors (2) to direct the fluid heat carrier to the return pipe (8) of the primary circuit. The solar collectors (2) necessary for reach said setpoint temperature. In case the temperature is higher than the setpoint temperature at the outlet of the first solar collector (2) of the collector battery (1), it increase the speed of the circulation pump (4) to increase the Flow rate of heat transfer fluid.

When what is desired is to have a flow constant in the heat transfer fluid, the control system (6) acts on the circulation pump (4) to adjust the speed of it and move the required flow.

If a constant flow and temperature is required at the outlet of the collector battery (1), such as absorption cooling / air conditioning installations, the control system (6) acts on the valve system (3) and on the circulation pump (4). For this, the control system (6) sets a constant flow acting on the speed of the circulation pump (4), while acting on the valve system (3) to arrange the manifold battery (1) with one or another configuration, according to the temperatures marked by the output probes (10) of each solar collector (2) and by the temperature probe (9) located in the return line (8) of the primary circuit. This ensures a constant flow and temperature at all times at the outlet of the battery
collectors (1).

This configuration allows to reach a wide temperature range at the outlet of the collector battery (1), from + 40ºC to + 150ºC.

Hot water can be used directly by a consumption circuit (industrial application preferably, domestic hot water production, heating, cold by absorption), yielding energy by means of heat exchangers heat (5).

Depending on its use, time and time of the year will be necessary the contribution in a certain percentage of a source of auxiliary energy, which will depend on the number of collectors solar (2) installed.

By means of the present invention the annual percentage that will be necessary to contribute of said auxiliary energy is determined a priori and, comparing it with the cost of the installation, to be able to optimize the investment.

All components of the solar installation thermal are characterized because they will meet the standards necessary to work correctly with temperatures of heat transfer fluid up to 180 ° C.

Claims (7)

1. Versatile solar thermal system for producing hot water up to high temperature, based on a solar thermal installation, consisting of a battery (1) of two or more solar collectors (2) with no limit of units, valve system (3), circulating pump (4), consumption circuit heat exchanger (5), control system (6), heat transfer fluid supply pipe (7), heat transfer fluid return pipe (8), temperature probe (9) at the outlet of the return pipe (8), temperature probe (10) at the exit of each solar collector (2), characterized in that said versatility allows the system object of this document to reach operating temperatures in the primary circuit between + 40ºC and + 150ºC. 2. Versatile solar thermal system for producing hot water up to high temperature, according to claim 1, characterized in that said operating temperatures are achieved by maintaining temperature, flow or both values simultaneously in the heat transfer fluid at the battery outlet (1) of solar collectors (2), which allows the use of solar energy in all types of industrial systems, heating, domestic hot water and cold absorption. 3. Versatile solar thermal system for producing hot water up to high temperature, according to claims 1 and 2, characterized in that the battery (1) of solar collectors (2) will be formed by flat solar collectors (2) or vacuum tubes, not using solar radiation concentration systems or other special solar collector. 4. Versatile solar thermal system for producing hot water up to high temperature, according to claims 1 to 3, characterized in that at least two solar collectors (2) will be arranged, varying the number thereof according to the size and needs of the installation and without units limit 5. Versatile solar thermal production system hot water up to high temperature, according to claims 1 and 2, in which the control system (6) is responsible for achieving said versatility, acting on the battery configuration of manifolds (1), as well as on the pump speed of primary circuit circulation (4). It will be possible to regulate the flow and temperature available and necessary in the circuit consumption. 6. Versatile solar thermal system for the production of hot water up to high temperature, according to claim 1 to 5, characterized in that all the components of the installation will meet the necessary standards to be able to work correctly with heat transfer fluid temperatures of up to 180ºC. 7. Versatile solar thermal system producing hot water up to high temperature, according to claim 1, characterized by the existence of an auxiliary power source, to meet the needs of heat transfer fluid consumption. A priori , and according to the number of solar collectors (2) available to the solar installation, you can determine the annual percentage of said auxiliary energy that will be necessary to provide and, comparing it with the total cost of the installation, also determine the profitability of the investment.