Hot water heating system comprising one or more water heaters with at least one water heating mechanism, and a heating-control storage tank generally configured to store heated water in a temperature stratified manner where hotter water tends to be separated from cold water. The heating-control storage tank can receive thermal energy or hot water from the water heater, send thermal energy or water to the water heater as its makeup water, and provide hot water directly to end users. The water heater may or may not be used to provide hot water to end users. The system is electronically controlled using a processor, various sensors, a recirculation pump, and electronically actuated valves. Depending on hot water needs and energy costs, the system controls water heating schedule and amount of hot water stored in the heating-control storage tank by changing system operation modes to minimize energy costs while providing reliable service.

A dual energy gas water heater is described and wherein a square flange, curved resistor style resistive heating element, is secured in a bottom portion of the tank of the water heater spaced above a top wall of the combustion chamber. A gas burner is secured in the combustion chamber and connected to a gas supply line through a gas valve. The curved resistive heating element is a low density, long life, element having a density in the range of about 20 to 80 watts/sq. inches. A switch is secured between the thermostat of the resistive heating element and the voltage supply line. A controller selectively operates the switch and the gas valve to disconnect the voltage supply line from the thermostat and/or shut-off the gas valve secured to the gas supply line depending on the desired source of energy. The controller is adapted to be optionally controlled by a utility/provider through a communication link. Renewable energy source may also be secured to an additional resistive heating element to improve the efficiency thereof.

An air conditioning system includes a heat pump having a refrigerant radiator, a gas furnace unit having a heating section to heat passing air, a blower generating air flow through the radiator and the heating section, and a controller controlling operation of the heat pump unit, the gas furnace unit, and the blower. The controller has a first operating mode in which the gas furnace unit operates alone as a heat source unit, a second operating mode in which the heat pump unit operates alone as a heat source unit, and a third operating mode in which the gas furnace unit and the heat pump unit operate at the same time as a heat source unit. The controller is configured to select the operating modes based on a parameter relating to outside air temperature that is the temperature of outside air.

A method and system of providing hot water efficiently. A cost of heating a volume of water to a predetermined temperature in a first water heater is determined. A cost of transferring a volume of hot water from a second water heater of a network of interconnected water heaters to the first water heater is determined. Upon determining that the cost of transferring the volume of hot water from the second water heater is lower than the cost of heating the volume of water of the first water heater, the second water heater transfers at least part of the volume of hot water to the first water heater. Otherwise, the volume of water is heated to the predetermined temperature in the first water heater.

A local heating system is presented. The local heating system comprising: a first heat source (10) connectable to a heating grid (110) and arranged to extract heat from the heating grid (110); a second heat source (20) connectable to an electrical energy grid (120) and to transform electricity feed through the electrical energy grid (120) into heat; a heat emitting device (30); a distribution system (40) for circulating heat transfer fluid between the heat emitting device (30) and the first and second heat sources (10, 20); and a controller (50) configured to control the first and second heat source's (10, 20) relative outtake of heat from the heating grid (110) and the electrical energy grid (120), respectively.

A local heating system is presented. The local heating system comprising: a first heat source (10) connectable to a heating grid (110) and arranged to extract heat from the heating grid (110); a second heat source (20) connectable to an electrical energy grid (120) and to transform electricity feed through the electrical energy grid (120) into heat; a heat emitting device (30); a distribution system (40) for circulating heat transfer fluid between the heat emitting device (30) and the first and second heat sources (10, 20); and a controller (50) configured to control the first and second heat source's (10, 20) relative outtake of heat from the heating grid (110) and the electrical energy grid (120), respectively.

Embodiments described herein generally relate to a domestic hot water (DHW) preheater operable to supply domestic hot water to a structure and/or to preheat a cold return of a space heating system.

A system and approach for developing a periodic water usage profile and demand for controlling a water heater. A mode may be selected for demand for a certain amount of water of a particular temperature range to be available for use from the water heater. Data on hot water usage may be collected and the usage profile and demand may be calculated from the data. The water heater may be programmed to operate in a certain fashion based on the usage profile and demand. A control knob may be on the water heater control to select a particular demand. Control of the water heater may be operated from a remote device connected in a wireless or wired fashion. An optimization program may be implemented in the control of the water heater for achieving one or more beneficial goals related to water heater performance and hot water production.

An air conditioning system includes a heat pump unit including a radiator usable with a refrigerant, a gas furnace unit including a heating section arranged to heat passing air, a blower arranged to generate an air flow that passes through the radiator and the heating section, and a controller configured to control each action of the heat pump unit, the gas furnace unit, and the blower. The controller operates either the heat pump unit or the gas furnace unit as a heat source unit, generates a capacity command used to variably adjust operating capacity of the heat source unit, and executes switch control in order to switch the heat source unit from either one of the heat pump unit or the gas furnace unit to the other when an operating capacity level designated in the capacity command is within a predetermined numerical range for a predetermined time.

A system for space heating or cooling a heated space includes a heat pump including a refrigeration circuit for transferring heat between a heat source and a heat load for heating and cooling operations. A controller controls the heat pump to perform the heating and cooling operations. A user interface receives user inputs, wherein the user inputs include an indication of discomfort based on temperature. The controller creates a profile for a minimum comfortable temperature level and a maximum comfortable temperature level, and the controller controls the heat pump to perform the heating and cooling operations in accordance with the profiles for the minimum and maximum comfortable temperature levels. The controller may generate an optimized heat demand plan in accordance with predictions of outdoor and indoor temperature, cost, and demand. The plan is optimized to cost-effectively maintain the temperature of the heated space within the comfortable temperature range defined by the profiles.