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.

A hot water recirculation system for a house or other building causes water to be recirculated to a water heater for reheating until the water is above a set-point temperature at which time the heated water is made available for use at a faucet or other hot water plumbing fixture. Recirculation of hot water takes place only when there is demand for hot water at a hot water plumbing fixture. A flow switching module for use in the hot water recirculation system can selectively direct water supplied to the flow switching module from a water heater either to a hot water plumbing fixture or to return piping for returning the water to the water heater. The flow switching module may be operated manually, automatically, or semi-automatically.

Control process of a thermal plant including a distribution circuit for a carrier fluid having a delivery line and a return line, a central thermal treatment group placed on the circuit, and channels, each of which is hydraulically interposed between the delivery line and the return line to serve respective environments. For each of the channels, the plant includes a respective exchange unit, a flow regulator to regulate a flow rate of carrier fluid through in the respective channel, an ambient temperature detector, a temperature detector of the carrier fluid for detecting a delivery temperature of the carrier fluid in each channel, and a return temperature of the carrier fluid in each channel. The process also includes a thermal optimization procedure as a function of ambient temperature, delivery temperature and return temperature of the carrier fluid.

A combined heat and power system for greenhouse carbon dioxide enrichment purifies carbon dioxide from exhaust gas of the combined heat and power system generating and supplying power and heat by combusting fuel and supplies the purified carbon dioxide to a greenhouse. The combined heat and power system includes a unified pipe system configured to simultaneously transmit hot water and carbon dioxide through a single pipe by dissolving the purified carbon dioxide in a heat transmission medium, a storage system configured to store the carbon dioxide transmitted to demand destinations along with the hot water, and supply unit configured to supply the carbon dioxide transmitted to and stored in the demand destinations depending on a heat and carbon dioxide load condition of a demand destination.

For balancing a hydronic network that comprises a plurality of parallel zones with a regulating valve in each zone, individual flow characteristics are determined (S1) for each of the regulating valves, by recording the total flow of fluid measured at different valve positions of a respective regulating valve, while the remaining other regulating valves are set to a closed valve position. Dependent flow characteristics are determined (S2) by recording the total flow of fluid measured at different valve positions of the respective regulating valve, while the remaining other regulating valves are set to an open valve position. Correction factors are determined (S3) for each of the regulating valves, using the individual flow characteristics and the dependent flow characteristics. The hydronic network is balanced (S4) by setting the valve positions of the regulating valves using target flows and the correction factors.

A method for balancing mass flow during production failure or insufficiency in a district heating network comprising a plurality of substations, each substation comprising at least one primary side connected to the district heating network for transferring heat between the district heating network and the substation, a secondary side connected to least one space heating circuit for heating at least one space connected to the substation, and an adjustable valve arranged between the substation and the district heating network, the valve (102) in each substation being controlled by a heat curve f defining a calculated supply temperature (Tsupply, calc) for the space heating circuit on the secondary side of the substation as a function of a measured outdoor temperature (Toutdoor). The method further comprises a step of heat curve compensation for each substation and population compensation for all substations in the population. The result is then used to control the valve in the respective substation.

A method for controlling a district thermal energy distribution system is presented. The method comprises: determining whether a local pressure difference between a feed line (111) and a return line (112) of a distribution grid (110) is below a predetermined threshold; upon the local pressure difference is determined to be below the predetermined threshold, generating a control signal comprising information instructing a local distribution system (150) to reduce outtake of heat or cold from the distribution grid (110); sending the control signal to a local control unit (140) of the local distribution system (150); and reducing, in response to the control signal, the outtake of heat or cold of the local distribution system (150) from the distribution grid (110). The distribution grid (110) may be a district heating grid or a district cooling grid. Also, a control server and a district thermal energy distribution system is presented.

When a hot water supply operation is started, a single mode is used in which hot water is output only from a second hot water supply circuit of a water heater, by cut-off of a flow path in a first hot water supply circuit of a space-heating water heater by a cut-off mechanism. When a load imposed by hot water supply by the second hot water supply circuit increases during the hot water supply operation in the single mode, the cut-off mechanism is opened to start hot water output from the first hot water supply circuit and a hot water supply operation in a parallel mode is performed in which hot water is output from both of the first hot water supply circuit and the second hot water supply circuit.

A fluid transportation network (1) comprises a plurality of parallel zones (Z1, Z2), fed by a common supply line (L), with a regulating zone valve (V1, V2) in each zone (Z1, Z2) for regulating a flow of fluid (ϕ.sub.1, ϕ.sub.2) through the respective zone (Z1, Z2). A processing unit (RE) receives valve positions (pos.sub.1, pos.sub.2) of the regulating zone valves (V1, V2) and determines and sets an adjusted valve position for a line valve (VE) arranged in the supply line (L), depending on the valve positions (pos.sub.1, pos.sub.2) of the regulating zone valves (V1, V2). A processing unit (RE) further receives a measurement of a total flow of fluid (ϕ.sub.tot) through the supply line (L) and determines and sets adjusted valve positions for the regulating zone valves (V1, V2), depending on the measurement of the total flow of fluid (ϕ.sub.tot) through the supply line (L).

A greenhouse, for cold weather climates, is configured with a gable that is offset toward the north wall and therefore the south extension of the roof, from the gable to the south wall is longer than the north extension. A greater amount of light can enter through this south extension and the inside surface of the north wall is configured with a reflective surface to allow light to be more uniformly distributed around the plants. The north wall may have no widows and may be thermally insulated to prevent the greenhouse from getting too cold during the night. A ground to air heat transfer (GAHT) system may be configured to produce a flow of greenhouse air under the greenhouse for heat transfer, to moderate the temperature of the greenhouse. A thermal medium may flow to a thermal reservoir for heat exchange with the conduits of the GAHT system.