Heating system for buildings

Abstract

Heating system (10) for buildings, comprising: a photovoltaic system (11); a high-temperature solid storage system (12), wherein the photovoltaic system (11) is configured to heat the high-temperature solid storage system (12); a heat exchanger (13) wherein the heat exchanger (13) is configured to extract heat from an output circuit of the high-temperature solid storage unit (12) and feed it into a heating circuit (20) at least during a first heating phase; a heat pump (14) wherein a probe circuit of the heat pump (14) is configured to extract heat indirectly or directly from the output circuit of the high-temperature solid storage (12) in a second heating phase and feed it into the heating circuit (20).

Description

TECHNICAL AREA

[0001] The invention relates to a heating system with a high-temperature solid storage unit for existing and new buildings. In particular, the invention relates to a heating system based on a combination of a heat pump with a high-temperature solid storage unit and a photovoltaic system (PV system). BACKGROUND

[0002] A photovoltaic system generates solar energy primarily during periods of low heating demand, namely in summer. An air-source heat pump ideally requires the conversion of existing buildings to underfloor heating, as it operates most efficiently at a flow temperature that is too low for wall-mounted radiators. A ground-source heat pump, due to the necessary deep drilling or the required horizontal ground probes, is often a very complex solution for the vast majority of existing buildings. A sand storage tank requires a comparatively large volume to bridge the months of low solar yield in late autumn, winter, and spring.

[0003] The present application addresses the objective of providing a heating system for existing and new buildings that, on the one hand, enables a high degree of heating energy self-sufficiency and, on the other hand, requires comparatively little space and investment. This objective is achieved with a heating system according to claim 1. Advantageous embodiments are described in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS The Fig. Figure 1 shows a simplified overview diagram of the functional blocks of a heating system according to an embodiment in which the heat exchanger and heat pump are arranged functionally parallel to each other. The Fig. Figure 2 shows a simplified overview diagram of the functional blocks of a heating system according to an embodiment in which the heat exchanger and heat pump are functionally arranged one behind the other. The Fig. Figure 3 schematically shows a storage phase of a heating system according to one embodiment. The Fig. Figure 4 schematically shows a first heating phase of the heating system of the Fig. 3. The Fig. Figure 5 schematically shows a second heating phase of the heating system. Fig. 3 The Fig. Figure 6 schematically shows the second heating phase alternatively with underfloor heating. DETAILED DESCRIPTION

[0004] The current energy situation is characterized by a discrepancy between high heat demand in winter, when solar energy supply is minimal, and a large surplus of PV electricity in summer, which is either insufficiently used due to a lack of storage options or fed into the grid for only a low remuneration.

[0005] The structural situation in existing buildings consists of an existing heating distribution system with radiators that require high flow temperatures (55-70°C), which prevents the efficient use of standard heat pumps or leads to uneconomically high operating costs.

[0006] The energy policy situation is characterized by the goal of complete decarbonization in the private heating sector versus a growing desire for autarky and security of supply, especially in times of crisis, in the face of volatile energy prices and geopolitical uncertainties.

[0007] The invention combines a PV system, a high-temperature solid storage system and a heat pump into a heating system that eliminates the disadvantages of using the components individually and enables complete or at least extensive self-sufficiency.

[0008] The heating system uses solar energy harvested during the summer months for heating during the winter months. The system comprises a photovoltaic (PV) system, a high-temperature solid-state storage tank, and a heat pump to supply underfloor heating and / or wall-mounted radiators in a building. During a storage phase in the summer, excess energy from the photovoltaic system heats the high-temperature solid-state storage tank. In the first heating phase of the heating season, the stored high-temperature heat is transferred via a heat exchanger to the wall-mounted radiators and / or underfloor heating system at a suitable flow temperature.In a second heating phase of the heating season, after the high temperature has been consumed, the residual temperature in the high-temperature solid storage tank is used as a booster for the heat pump, whose efficiency can be increased to such an extent that no further external energy needs to be supplied to heat the building until the end of the heating season, thus enabling largely year-round energy self-sufficiency for new and existing buildings.

[0009] The thermal energy from the high-temperature solid storage tank can be fed directly into a heating circuit with wall-mounted radiators via a simple heat exchanger, down to a lower threshold temperature of approximately 60 degrees Celsius, or directly or via a heat exchanger into a heating circuit for underfloor heating, down to a lower threshold temperature of approximately 40 degrees Celsius. If the temperature in the high-temperature solid storage tank falls below the lower threshold temperature, the thermal energy from the high-temperature solid storage tank is fed directly or indirectly into the probe circuit of the heat pump.

[0010] The efficiency of a heat pump increases with a decreasing temperature difference between the heating circuit and the ground loop. The temperature of the heat transfer medium in the ground loop of a heat pump with a conventional ground source heat exchanger is typically around 10 degrees Celsius in winter, and can drop to double-digit sub-zero temperatures in an air source heat pump. Consequently, the energy input required from the outside for these heat pumps is correspondingly high. In contrast, the high-temperature solid storage tank in the heating system according to the invention can heat the heat transfer medium in the ground loop of the heat pump to a temperature significantly above 10 degrees Celsius for an extended period. As long as the temperature in the high-temperature solid storage tank remains above the temperature in the ground loop of a heat pump with a conventional ground source heat exchanger at the point of use, the heat pump in the heating system according to the invention operates with significantly higher efficiency than the same heat pump when supplied with a conventional ground source heat exchanger.

[0011] The effort required for deep drilling or the covering of the area by a surface probe in the vicinity of the building to be heated is eliminated.

[0012] The Fig. 1 and Fig. Figure 2 each shows a heating system 10 for a building. The heating system comprises a photovoltaic system 11, a high-temperature solid-state storage tank 12, a heat exchanger 13, and a heat pump 14. The photovoltaic system 11 is configured to heat the high-temperature solid-state storage tank 12. The heat exchanger 13 is configured to extract heat from an output circuit of the high-temperature solid-state storage tank 12 and feed it into a heating circuit 20 of the building, at least during an initial heating phase. A probe circuit of the heat pump 14 is configured to extract heat, directly or indirectly, from the output circuit of the high-temperature solid-state storage tank 12 and feed it into the heating circuit 20 during a second heating phase following the initial heating phase.

[0013] In heating system 10 of the Fig. The heat exchanger 13 is configured to extract heat from the output circuit of the high-temperature solid storage tank 12 only during the first heating phase and feed it into a heating circuit 20. The probe circuit of the heat pump 14 is configured such that, during the second heating phase, heat is fed directly from the output circuit of the high-temperature solid storage tank 12 into the probe circuit.

[0014] In heating system 10 of the Fig. 2 The heat exchanger 13 is integrated into the high-temperature solid storage tank and extracts heat from the output circuit of the high-temperature solid storage tank 12 in both the first and second heating phases. In the first heating phase, the heat exchanger 13 feeds heat into the heating circuit 20 and in the second heating phase into the probe circuit of the heat pump 14.

[0015] In both cases, the heating system 10 can also include the heating circuit 20 of a building. The heating circuit 20 has at least one wall-mounted radiator 21 or at least one installed underfloor heating coil. The heating system 10 can include a temperature sensor 16 configured to detect the temperature of the high-temperature solid storage tank 12 and / or the temperature of a heat transfer medium circulating in the outlet circuit of the high-temperature solid storage tank 12. Shut-off valves 18 allow individual heat transfer circuits to be temporarily shut off.

[0016] A control unit 17 controls the shut-off valves 18 depending on the temperature detected by the temperature sensor 16, according to the first and second heating phases described above. In the examples shown, for the first heating phase, the control unit 17 closes the shut-off valves 18 controlled by a first control signal S1 and opens the shut-off valves 18 controlled by a second control signal S2. For the second heating phase, the control unit 17 opens the shut-off valves 18 controlled by the first control signal S1 and closes the shut-off valves 18 controlled by the second control signal S2.

[0017] The in the Fig. 1 + Fig. The two shown shut-off valves 18 and control units 17 as well as temperature sensors 17 can of course be omitted if the shut-off and coupling of the individual heat transfer circuits is not to be done automatically, but manually.

[0018] The heating system 10 of the Fig. Figures 3 to 5 show a PV system 11 in combination with an optional, intelligent and dynamic electricity tariff manager for storing energy in a seasonal high-temperature solid storage tank 12 (e.g., sand), which is charged to a high temperature level of several hundred degrees Celsius. Connected to this, via heat exchangers 13 with regulators, is the existing heating system with high flow temperatures in existing buildings and a switchover to the heat pump 14, which, after the stored high-temperature energy has been used up, is powered by the residual heat from the high-temperature solid storage tank 12.

[0019] The heating system operates in three phases. Fig. Figure 3 shows a storage phase in months with PV surplus (summer). During the storage phase, the high-temperature solid-state storage tank 12 is charged with energy. Depending on the size of the PV system 11, solar energy can also be used in the house for hot water production via a solar boiler or instantaneous water heater, for wallboxes for electric vehicles, and for daily electricity needs. The PV system can also supply the control current for pumps and controllers.

[0020] The Fig. Figure 4 shows an initial heating phase in early winter, e.g., from October to December. In existing buildings with radiators that require high flow temperatures, the high-temperature heat stored in the high-temperature solid storage tank is used. A heat exchanger system extracts heat from the hot high-temperature solid storage tank to heat water directly to the required temperature for the radiators. The heat pump remains switched off during this time. Operation is virtually free. Electricity is only required for the pumps and can also be generated by the photovoltaic system. Any surplus PV power can be used to further charge the high-temperature solid storage tank.

[0021] The Fig. Figure 5 shows a second heating phase in late winter, e.g., January to April. The high-temperature energy of the high-temperature solid storage tank 12 has been used up. The high-temperature solid storage tank 12 has cooled to a residual temperature of, e.g., 30°C. The heating system 10 now uses the residual heat of the high-temperature solid storage tank 12 as a booster for the heat pump 14.

[0022] The residual heat from the high-temperature solid storage tank 12 now serves as a heat source for the heat pump 14, which thus operates far more efficiently than an air-source heat pump in freezing cold outside air or a ground-source heat pump at a ground temperature of approximately 10 °C. From February at the latest, the high-temperature solid storage tank 12 can be recharged using PV electricity generation. Any temporary electricity shortages later on can be met at any time via intelligent tariff management from dynamic electricity tariffs, ensuring the heating of the existing building throughout the entire heating season.

[0023] The Fig.Figure 5 shows a coupling with underfloor heating: A further increase in efficiency results from the combination with underfloor heating, e.g., in new buildings or during the renovation of existing buildings. This can drastically reduce high-temperature consumption in the first phase of the energy discharge of the solid-state thermal storage system, so that with this construction method, complete year-round self-sufficiency for electricity / heat demand results, and / or a significant reduction in the required solid-state storage volume.

[0024] Technical advantages: Firstly, the invention solves the problem of existing buildings because it is fully compatible with high-temperature radiators, eliminating the need for expensive renovations of the distribution system or the installation of underfloor heating. Secondly, by utilizing the residual heat from the sand storage tank in the second half of winter, the considerable costs for the probes required for a geothermal heat pump are eliminated. Furthermore, the invention closes the gap between energy supply in summer and energy demand in winter through a genuine storage concept. Another important advantage is its extreme resilience – the system functions autonomously for weeks or months during a winter power outage (only the continued PV power supply for the pumps is required). Moreover, the principle outlined here is scalable to virtually any size, from single-family homes to small residential areas.

[0025] The invention of seasonal heat storage using solid-state storage in combination with a heat pump has the potential to solve one of the core challenges of the energy transition in the building sector. It enables true, year-round energy independence and makes decarbonization technically elegant and possible without loss of comfort, even for existing buildings with high-temperature systems.

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