A waste-heat recovery system includes a compressor main body; a gas piping, a waste-heat-recovery heat exchanger, a circulation circuit, and a tank with a water inlet piping and a water outlet piping that stores water that exchanges heat with the heat medium by connecting to the circulation circuit. The waste-heat recovery system also includes an inlet valve, a circulation pump, and a gas temperature sensor that detects the temperature of the compressed gas by arranging in the gas piping. The waste-heat recovery system also includes a water temperature sensor that detects the temperature of the water in the tank, and a control device that controls the inlet valve and the outlet valve according to detection temperature of the gas temperature sensor and the water temperature sensor.

A heat exchanger, comprising at least a double shell, wherein the lower portion of the inner space of the inner shell is filled with liquid phase change medium, and at least one coiler is provided in the upper portion. The heated fluid flows in the coiler. After the downstream side pipe of the coiler is pierced through the inner shell, at least one surrounding pipe is formed in the cavity between the double shells. The bottom heat exchange plate of heat exchanger of the inner shell is located above the heat source. The cavity between the two shells forms the flue gas passage. After bottom heat exchange plate of the inner shell is heated by the heat source, the flue gas rises from the bottom of perimeter of the inner shell along the flue gas passage and the heat is transferred to the heated fluid in the surrounding pipe. The heat device using the heat exchanger according to the present invention can significantly improve the efficiency of heat utilization.

A combined heat, cooling and power system is configured to generate energy as well capture a large percentage of energy that would otherwise be lost using components, including heat transfer components, embedded within a vessel to transfer energy in the form of heat to liquid within the vessel.

The purpose of the present invention is: to enable hot water at a required temperature to be supplied, even in cases when compressor load factor is low; to suppress heat dissipation from a waste-heat recovery device; and to improve waste-heat recovery rate. A waste-heat recovery system in an oil-cooled gas compressor is provided with: a compressor main body (3); an oil separator (6); gas piping (8) which supplies, to a demanded destination, compressed gas separated from oil by the oil separator; oil piping (7) which returns, to the compressor main body, the oil separated by the oil separator; and a waste-heat-recovery heat exchanger (10) which recovers heat from the compressed gas and/or the oil. The waste-heat recovery system is also provided with: a hot-water storage tank (19); circulation circuits (17, 18) in which a heat medium is made to circulate between the waste-heat recovery heat exchanger and the hot-water storage tank; a circulation pump (22) provided to these circulation circuits; and a control device (32) which, in cases when the temperature of the oil or the compressed gas subjected to heat exchange in the waste-heat-recovery heat exchanger is equal to or less than the temperature of the hot water in the hot-water storage tank, stops the circulation pump or reduces the rotational frequency of the circulation pump.

The present invention provides a hot water storage-type boiler having both a heat amount proportional control function and a backflow prevention function to prevent a backflow of exhaust gas with a simple structure. In the present invention, since a check valve is integrally coupled to a burner duct, there is an effect of convenient assembly. In addition, since the check valve is built in the burner duct, the check valve does not protrude to the outside, thereby having an effect that a separate space is not required.

A heat exchanger assembly includes at least one coil shaped heat exchanger pipe assembly for passing through a fluid to be heated, which has an inlet, an outlet and coil windings extending concentrically around a coil axis. The heat exchanger assembly further includes a housing in which the heat exchanger pipe assembly is received, such that a flue gas transport gap extends between the heat exchanger pipe assembly and the circumferential wall. In use, hot flue gas passes the coil windings, thereby imparting the heat to the fluid present in the heat exchanger pipe assembly. The housing has a first and a second end wall which close off a first end and a second end of the circumferential wall. The housing is made of plastic and the heat exchanger pipe assembly is clamped in axial direction between the first and the second end wall of the plastic housing.

The present disclosure discloses a water heater, and a scale detection system and method. The scale detection system comprises: a first temperature detector configured to acquire a first temperature of a heat exchange zone of a water heating device; a second temperature detector configured to acquire a second temperature indicating a water temperature in the water heating device; and a controller in communication with the first temperature detector and the second temperature detector, and configured to acquire a temperature difference between the first temperature and the second temperature based on the first temperature acquired by the first temperature detector and the second temperature acquired by the second temperature detector, and determine that a scale generation amount in the water heating device reaches a preset threshold when at least one of the following judgment conditions is met: the first temperature is not less than a preset temperature threshold; and the temperature difference is not less than a preset temperature difference threshold. The present disclosure can ensure that a user can be reliably and timely reminded to clean the scale under different working conditions.

A water heater includes a thermally isolating preheater using a phase change material for increased efficiency. Cold water passes through the preheater and is heated using the phase change material therein. Due to the preheater, heated water is supplied to the water contained in the water heater storage tank.

A water heater can include a tank. The water heater can also include a heat exchanger that includes multiple flue tube segments disposed within the tank, where the flue tube segments include a thermally-conductive material. The heat exchanger can further include a heating system that heats a fluid to create a heated fluid, where the heating system further circulates the heated fluid through the flue tube segments, where the flue tube segments absorb thermal energy from the heated fluid and subsequently dissipate the thermal energy into the tank to convert the unheated water to the heated water. The water heater can also include a controller coupled to the heating system, where the controller operates the heating system outside of a normal heating cycle when the controller determines that condensation has accumulated in the flue tube segments, where operating the heating system outside of the normal heating cycle removes the condensation.

A hot water heater appliance includes a boiler, a companion water heater and a controller. The controller is configured to control the water heater appliance in response to a scheduled plurality of performance modes based on a preset schedule. A first performance mode is scheduled to be performed at an expected low usage time and a second performance mode is scheduled to be performed at an expected high usage time relative to the expected low usage time.