A combined cooling and heating system including a district cooling grid having a feed conduit for an incoming flow of cooling fluid having a first temperature, and a return conduit for a return flow of cooling fluid having a second temperature, the second temperature being higher than the first temperature; a local cooling system being configured to absorb heat from a first building and comprising a heat exchanger having a heat exchanger inlet and a heat exchanger outlet; and a local heating system being configured to heat the first or a second building and comprising a heat pump having a heat pump inlet and a heat pump outlet. The heat exchanger inlet is connected to the feed conduit of the district cooling grid; and the heat pump inlet is connected to the return conduit of the district cooling grid and to the heat exchanger outlet.

The invention concerns a district energy system comprising: - at least one cogeneration or heat pump unit, - a first pipe system for district heating and/or cooling consisting of at least one liquid or vapor CO.sub.2 pipe; characterized by the fact that is also comprises a second pipe system consisting of at least one fluid line for the transport of CO.sub.2 or O.sub.2. The invention also relates to the use of a district energy system comprising: - at least one cogeneration or heat pump unit, - a first pipe system, - a second pipe system; characterized by the fact that that liquid or vapor CO.sub.2 is used in the first pipe system for district heating and/or cooling and that a fluid of CO.sub.2 or O.sub.2 is used in the second pipe system.

The invention provides a system for energy distribution that uses liquid carbon dioxide as a working fluid. Evaporation of the carbon dioxide provides cooling, and compression of the carbon dioxide gas back to the liquid state provides heat. The amount of heat transferred at both stages is sufficient to provide environmental heating and cooling. Waste thermal energy from a power plant, in the form of hot water, is fed into the system and used to drive the overall process. An underground thermal energy storage system is used to store energy flowing into the system that is in excess of the current demand.

A system (15) regulates a temperature of fluid in a sector of a fluid distribution network, including a feed line (11) transporting fluid from a thermal energy source (3) to a thermal energy consumer (7) within the sector and a return line (13) transporting fluid back. A bypass line (17) connects the return line to the feed line, mixing fluid from the return line into the feed line. A pump is at the bypass line. A temperature sensor determines a temperature of fluid in the feed line downstream of the bypass line. A pressure sensor determines an uncontrolled pressure difference between the feed line and the return line, or an uncontrolled pressure difference correlated therewith. A control unit controls the speed of the pump with a closed-loop control for achieving a target feed line temperature based on the determined temperature, and a feed-forward control compensating fluctuations of the pressure difference.

Thermal energy systems for managing, distribution and recovery of thermal energy. A single-pipe loop circulating a two-phase refrigerant is provided. The single-pipe loop is spread through the entire system and interconnects a plurality of local heat exchange stations, each having different thermal energy loads. A central circulation mechanism (CCM) is also provided for circulating the refrigerant for distribution of thermal energy within the system.

The present invention relates to a method for controlling one or more heat pumps (110) connected to a distribution grid (10) for fluid-based distribution of heating and cooling in order to, at least partly, compensate for a cold outtake from the distribution grid (10) by a first cooling machine (120) connected to the distribution grid (10). Alternatively, or in combination, one or more cooling machines (120) connected to the distribution grid (10) may be controlled in order to, at least partly, compensate for a heat outtake from the distribution grid (10) by a first heat pump (120) connected to the distribution grid (10). The controlling is made a control server (200) monitoring outtake of heat and/or cold from the distribution grid (10) by the heat pumps (110) and cooling machines (120) connected to the distribution grid (10). The control server (120) generates and sends out control messages to the heat pumps and/or cooling machines.

A hydronic floor heating system as it relates to an HVAC apparatus, approach and system. Aspects of the present system and approach may include a radiant floor optimization mode, low floor temperature in vacation mode, modifying a 300 Hz, or so, reading principle base on implementation of Pseudo-random jittering of a reading event improving short-term accuracy of the individual readings, and a combination of hardware and software filters for using thermal sensors with extended cable length.

Disclosed is a method for controlling a control valve (110), wherein the control valve (110) is configured to control a flow of heat transfer fluid to a thermal energy extraction unit (108). The method comprising: reviewing (S402) a demand signal for the control valve (110); checking (S404) if the demand signal is indicative of setting the control valve (110) in a hysteresis interval for the control valve (110); and upon the demand signal is indicative of setting the control valve (110) in the hysteresis interval, alternatingly (S406) setting the control valve (110) in an open state above the hysteresis interval and setting the control valve (110) in a closed state.

Auxiliary system for a low-temperature remote thermal energy distribution network (anergy network) connected to user thermal installations, comprising one or more heat pumps thermally coupled to the anergy network via a heat exchanger, one or more air-liquid heat exchangers thermally coupled to the outside air, and a hydraulic network interconnecting the heat pumps to the heat exchanger of the anergy network, at least one of the heat pumps being a liquid-air heat pump fluidically connected by the hydraulic network to at least one of said air-liquid heat exchangers. The auxiliary system further comprises a measurement, control and regulation (MCR) system. The hydraulic network comprises valves controlled by the MCR system and a hydraulic circuit configured to allow direct connection of said air-liquid heat exchangers to the heat exchanger of the anergy network.

A district energy distributing system comprising a geothermal power plant comprising a first and a second circuit. The first circuit comprises a feed conduit for an incoming flow of geothermally heated water from a geothermal heat source; a boiler comprising a heat exchanger configured to exchange heat from the incoming flow of geothermally heated water to superheat a working medium of a second circuit of the geothermal power plant; and a return conduit for a return flow of cooled water from the boiler to the geothermal heat source. The second circuit comprises the boiler configured to superheat the working medium of the second circuit; an expander configured to allow the superheated working medium to expand and to transform the expansion to mechanical work; and a condenser configured to transform the expanded working medium to liquid phase and to heat a heat transfer fluid of a district thermal energy circuit.