37 results about "Logarithmic mean temperature difference" patented technology

The invention discloses a large temperature difference centralized heating / cooling system. According to the large temperature difference centralized heating / cooling system, hot water output from a residual heat heating system can be divided into two ways: one way is connected with the cooling system through pipelines and the other way is connected with urban heat users through the pipelines; the cooling system is mixed with backwater of the heat supply users and then connected with heat users through the pipelines; the backwater of the heat supply users enters into an absorption heat pump in a heating system; the absorption heat pump is driven by steam or fuel gas to extract cooling circulating water residual heat; the residual heat is heated by a heater to the temperature of 130 DEG and heating water is discharged and enters into a next circulation. The large temperature difference centralized heating / cooling system has the benefits that as the back water of the system is recycled, the temperature of supply water / backwater reaches 130 / 30 DEG; as the temperature of the supply water / backwater is increased, the heat supply network delivery capacity is improved and the water pump power consumption in the system operation is reduced; moreover, an ammonium hydroxide absorption cooling unit can not only ensure cooling in winter, but also provide cold quantity for cold storages in spring, summer and autumn, power necessary for normal electric cooling is saved, the residual heat usage rate is improved and the energy conservation and emission reduction are facilitated.

A temperature regulating apparatus includes a heat exchanger and regulates a temperature of a first medium by performing heat exchange between the first medium and a second medium via the heat exchanger. A regulating operation unit generates a flow rate regulating signal so that the temperature of the first medium flowing out from a primary side outlet of the heat exchanger becomes equal to a target temperature. A control valve regulates a flow rate of the second medium based on the flow rate regulating signal. A correcting operation unit (a) calculates, based on temperatures detected by first, second, third and fourth temperature sensors, a heat exchange amount of the heat exchanger, a logarithmic mean temperature difference or an average temperature in the heat exchanger, and the flow rate of the second medium, (b) calculates an overall heat transfer coefficient of the heat exchanger based on the calculated heat exchange amount and the calculated logarithmic mean temperature difference or the calculated average temperature, and the flow rate of the second medium, (c) obtains a ratio (ΔG) of a change (Q2-Q′2) in the heat exchange amount to a change (ΔF2) in the flow rate of the second medium based on the calculated flow rate (F2) of the second medium and the calculated overall heat transfer coefficient (K), and (d) corrects a gain of the regulating operation unit based on the obtained ratio.

The invention provides an ocean thermal energy conversion method and an ocean thermal energy conversion device. The method comprises the following steps of: heating a low-boiling-point working medium by using hot seawater on a surface of ocean; evaporating the low-boiling-point working medium; feeding into a turbine to push a turbo generator set to work for power generation; condensing working medium gas which is exhausted from the turbine into liquid by using cold seawater on a deep layer of the ocean; heating by using the hot seawater; feeding into the turbine to make the working medium gasevaporated; pushing the turbo generator set to work for the power generation; cyclically executing the steps; and continuously carrying out power generation. Power is generated by using ocean surfacewind power, a heat pump device is driven by the power, the temperature of the working medium is further raised by using a medium of the heat pump device, and the volume expansion ratio of the workingmedium is improved; and the temperature of the cold seawater is further reduced by using the medium of the heat pump device, the working medium exhausted gas is condensed by using the low-temperatureseawater, and a condensing effect of the working medium exhausted gas is improved. The method and the device improve the efficiency of closed cycle generation of ocean thermal energy conversion, realize the comprehensive utilization of ocean thermal energy and wind energy, have an important practical value, provide environment-friendly energy sources, and are easy to use and promote in large scale.

A boosting vaporization device for recovering liquid oxygen cold energy comprises a nitrogen compression system, an expansion refrigeration system, a liquid oxygen boosting system and a heat exchange system which are connected with one another through pipelines and valves. The nitrogen compression system consists of a first circulating nitrogen compressor, a first circulating nitrogen compressor aftercooler, a second circulating nitrogen compressor and a second circulating nitrogen compressor aftercooler; the expansion refrigeration system is composed of a nitrogen pressurization expansion machine, a nitrogen expansion machine and other auxiliary parts, nitrogen circulation and cooperation of the nitrogen circulation and the liquid oxygen vaporization reheating process are utilized, so that the overall logarithmic average temperature difference of the heat exchanger is within an extremely low range, irreversible losses of the heat exchanger are greatly reduced, and the heat exchange efficiency is improved. Therefore, recovery of high-grade cooling capacity of the liquid oxygen is realized on the basis of pressurizing and vaporizing the liquid oxygen, and the recovered cooling capacity is embodied in the form of liquid nitrogen.

The invention discloses an operation switching adjusting device for heat exchangers and circulating pumps of a heat exchange station and a working method. The device comprises a control module, a heat exchange station water inlet manifold water temperature sensor, heat exchanger primary water outlet pipe water temperature sensors, heat exchanger primary water inlet pipe electric control valves, heat exchanger secondary water outlet pipe water temperature sensors, check valves, circulating pump frequency conversion speed regulators, a water distributor water temperature sensor, a water collector water temperature sensor, a water distributor and collector pressure difference sensor and heat exchanger secondary water return pipe electromagnetic valves. The logarithmic mean temperature difference is introduced to quantitatively describe the heat exchange capacity of the heat exchangers, and the logarithmic mean temperature difference of the heat exchangers is used as a criterion when the heat exchangers are increased or decreased. By taking the opening degree of an electric control valve, the frequency of the circulating pumps, the water supply temperature, the pressure difference and the keeping time of the parameters as criteria, the equipment operation switching working method of the heat exchange station with two typical structures of 'first series connection and then parallel connection' and 'first parallel connection and then series connection' of the heat exchangers and the circulating pumps is provided, and the heat supply amount adjusting range of the heat exchange station can be effectively widened.

The invention relates to a high-enthalpy heat island lead large on-way temperature difference and small heat transmission temperature difference back heating type air disinfector which comprises a high-enthalpy heat island and at least one atmospheric heat exchanger, wherein the atmospheric heat exchanger is connected with the high-enthalpy heat island, the outer end head of the atmospheric heat exchanger comprises an air inlet and an air outlet, the inner end head of the atmospheric heat exchanger comprises a low-temperature side air outlet and a high-temperature side air inlet, the air inlet at the outer end head is communicated with the low-temperature side air outlet of the atmospheric heat exchanger, the air outlet at the outer end head is communicated with the high-temperature side air inlet of the atmospheric heat exchanger, and the high-enthalpy heat island is positioned between the low-temperature side air outlet and the high-temperature side air inlet of the atmospheric heat exchanger. According to the invention, the high-enthalpy heat island lead is adopted, large on-way temperature difference and small heat transmission temperature difference are built inside the atmospheric heat exchanger, high-temperature air heat quantity after disinfection can be recycled, and the technical problems of incomplete disinfection, medicine residue, toxic and side effects and the like in conventional air disinfecting technology can be solved.

The invention discloses a modeling method of a proton exchange membrane fuel cell cooling system, a fuel cell is cooled by using a tubular strip-shaped finned heat exchanger, and the establishment ofa heat exchanger model is based on gas-liquid heat exchange, establishment of a specific model of the cooling system comprises seven steps of establishing an energy conservation equation, calculatingthe efficiency of a radiator, calculating the convective heat transfer between cooling liquid and a flat tube, calculating the heat conduction inside the tube wall, calculating the convective heat transfer between the outside of the flat tube and air, calculating the fin efficiency and calculating the heat transfer between the cooling liquid and an electric pile. The defects that an existing three-dimensional radiator model is low in calculation efficiency and cannot be directly used in a system model are overcome. The radiator model is based on efficiency-heat transfer unit number method, does not need an image logarithm average temperature difference method for iterative calculation, the calculation efficiency of the model is high, and enough model precision can be guaranteed.

The invention provides a tunnel-typed residual-heat recovery semiconductor temperature difference generation method and a device. The generation method is characterized in that a movable heat source which emits residual heat runs pass a tunnel-typed heat collector which receives the heat emitted by the movable heat source and transmits the collected heat to a heat surface of a semiconductor temperature difference generation module; a radiator is arranged at one side of a cooling surface of the semiconductor temperature difference generation module; the cooling surface is cooled to a temperature much lower than that of the heat surface by the radiator, thus generating a large temperature difference at two end surfaces of the semiconductor temperature difference generation module; the semiconductor temperature difference generation module directly converts the temperature difference into the electric potential difference which is used as a power supply after being converted by a stabilizer circuit and AC / DC. The device of the invention comprises the semiconductor temperature difference generation module, the tunnel-typed heat collector, and a radiator; the method and the device of the invention have the advantages that the recovered residual heat energy can be directly converted into electric power, the generation process has no noise, no abrasion and no medium leakage, furthermore, the generator has the small volume, light weight, convenient movement, maintenance-free and long service life, etc.

The invention discloses a phase change heat sink manufacturing process, and relates to the technical field of heat sink bonding, comprising the following steps of S1, disposing a mounting slot on themounting surface of a heat sink body; S2, embedding and fixing a PCB in the mounting slot, wherein a closed cavity is formed between the PCB and the bottom of the mounting slot; S3, exhausting the airin the closed cavity by a communication tube preformed on the heat sink body; S4, pouring a phase change medium into the closed cavity by the communication pipe; and S5, sealing the communication tube to form a uniform temperature phase change heat dissipation structure. The uniform temperature phase change heat dissipation structure is filled with the phase change medium so as to reduce the thermal resistance between the PCB and the heat sink body. Thus, the heat on the PCB is uniformly transferred to the surface of the heat sink body, and the transverse temperature difference among variouspoints on the surface of the heat sink body and the longitudinal temperature difference of the heat sink body are reduced, thereby achieving a purpose of improving the surface utilization rate of theheat sink body and a purpose of improving a heat dissipation effect.

The invention discloses a device and a working method for switching the operation of a heat exchanger and a circulating pump in a heat exchange station. Electric regulating valve of primary water inlet pipe, water temperature sensor of secondary water outlet pipe of heat exchanger, check valve, frequency conversion speed controller of circulating pump, water temperature sensor of water separator, water temperature sensor of water collector, differential pressure sensor of water collector and heat exchanger Solenoid valve of the secondary return pipe; the logarithmic average temperature difference is introduced to quantitatively describe the heat exchange capacity of the heat exchanger, and the logarithmic average temperature difference of the heat exchanger is also used as a criterion when adding or subtracting heat exchangers; the electric control valve opening, cycle Pump frequency, water supply temperature, pressure difference and the time for maintaining these parameters are used as criteria to provide equipment operation switching for heat exchangers and circulation pumps in two typical structures of heat exchange stations: "first in series and then in parallel" and "first in parallel and then in series". The working method can effectively improve the heat supply adjustment range of the heat exchange station.

The invention discloses a wet cooling unit condenser economic back pressure calculation method based on logarithmic average temperature difference and a genetic algorithm, and relates to the field of thermal power plant cold end system economical efficiency optimization. The invention aims at calculating the most economical back pressure of the condenser of the wet cooling unit so as to calculate the energy-saving effect of the most economical back pressure. The wet cooling unit condenser economic back pressure calculation method based on logarithmic average temperature difference and a genetic algorithm comprises the following steps: firstly, establishing a function between the power consumption of a circulating cooling water variable frequency pump and the back pressure of the condenser; and then, based on the function, calculating the back pressure corresponding to the maximum power supply power variation of the unit, and taking the back pressure as the most economical back pressure of the condenser.

The invention provides a heat exchanger with 2-20 flow paths. The heat exchanger with the 2-20 flow paths comprises 1-20 heat exchanger bodies. The heat exchanger with the 2-20 flow paths is characterized in that by the adoption of a method for increasing the number of the flow paths, the total length of a first medium flow channel and the total length of a second medium flow channel of the heat exchanger are increased, the total length of the first medium flow channel is made to reach 0.3-20 meters, the total length of the second medium flow channel is made to reach 0.3-20 meters, and finally it is achieved that the hot end temperature difference of the heat exchanger is lowered; and according to the method for increasing the number of the flow paths, the 2-20 flow paths are constructed in the inner structure of the heat exchanger or the 2-20 heat exchanger bodies constitute the 2-20 flow paths through series connection or the 2-20 heat exchanger bodies constitute the 2-20 flow paths through parallel connection and series connection. The heat exchanger with the 2-20 flow paths can achieve that the hot end temperature difference of the heat exchanger is controlled to be within 1 DEG C and is convenient to apply and popularize generally on heat exchange sites.