A system includes a detection interface that detects signals from which house data and environmental data for at least one house can be collected. The house data includes at least power usage of the heating ventilation and air conditioning (HVAC) system of the house as a function of time. An analyzer calculates values of thermal loads of the house based on the house data and the environmental data by solving a stochastic thermal energy balance equation for the house using thermal load estimates. An output interface outputs information about the thermal loads of the house based on the calculated thermal load values.

There is disclosed a device for determining a strength of an oscillating electric field. The device comprises an absorber to absorb radiation at the frequency of the oscillating electric field, and a thermal insulator transparent to radiation at the frequency of the oscillating electric field, which thermal insulator is arranged to thermally insulate the absorber. The device also comprises a first temperature sensor arranged to measure the temperature of the absorber, and a second temperature sensor arranged to measure the temperature external to the thermal insulator. Methods of measuring electric field using such a device, and methods of calibrating such a device, are also disclosed.

A system and method for interactively evaluating energy-related investments affecting building envelope with the aid of a digital computer are provided. Obtained is a total amount of fuel purchased for a building over a set period from which an existing amount of the fuel consumed for space heating is derived. Characteristics including thermal performance and furnace and delivery efficiencies of the building for both existing and proposed equipment are obtained, including remotely controlling a heating source inside the building. The thermal performance and furnace and delivery efficiencies characteristics of the existing and proposed equipment are expressed as interrelated ratios. An amount of fuel to be consumed for space heating is evaluated as a function of the existing amount of the fuel consumed for space heating and the ratios of the existing and proposed equipment.

A system and method for interactively evaluating energy-related investments affecting building envelope with the aid of a digital computer are provided. Obtained is a total amount of fuel purchased for a building over a set period from which an existing amount of the fuel consumed for space heating is derived. Characteristics including thermal performance and furnace and delivery efficiencies of the building for both existing and proposed equipment are obtained, including remotely controlling a heating source inside the building. The thermal performance and furnace and delivery efficiencies characteristics of the existing and proposed equipment are expressed as interrelated ratios. An amount of fuel to be consumed for space heating is evaluated as a function of the existing amount of the fuel consumed for space heating and the ratios of the existing and proposed equipment.

An apparatus and a method for determining a power value of a target in the form of an AC circuit (130; 230; 330) having an AC power source (132; 232; 332). The method involves operating (72) a controllable DC power source (12) to provide DC power to a DC circuit (10; 110; 210; 310) and measuring (73) at least one thermal parameter related to power dissipation of the DC circuit (10; 110; 210; 310) and of the target AC circuit (30; 130; 230; 330), wherein at least one heat sink (160a, 160b; 260; 360) is thermally coupled between the DC circuit (10; 110; 210; 310) and the target AC circuit (30; 130; 230; 330). The method further involves controlling (74) the DC power source (12) based on the measured at least one thermal parameter to reduce a difference in power dissipation between the DC circuit (10; 110; 210; 310) and the target AC circuit (30; 130; 230; 330). The method then involves, when thermal equilibrium is reached (75), determining the power value (49) of the target AC circuit (30; 130; 230; 330) by retrieving (76) at least one real-time measurement of at least one electric parameter of the DC circuit (10; 110; 210; 310), calculating (77) a DC power value of the DC circuit (10; 110; 210; 310) based on the retrieved at least one real-time measurement of the at least one electric parameter, and calculating (78) the power value (49) of the target AC circuit (30; 130; 230; 330) using the calculated DC power value.

An apparatus and a method for determining a power value of a target in the form of an AC circuit (130; 230; 330) having an AC power source (132; 232; 332). The method involves operating (72) a controllable DC power source (12) to provide DC power to a DC circuit (10; 110; 210; 310) and measuring (73) at least one thermal parameter related to power dissipation of the DC circuit (10; 110; 210; 310) and of the target AC circuit (30; 130; 230; 330), wherein at least one heat sink (160a, 160b; 260; 360) is thermally coupled between the DC circuit (10; 110; 210; 310) and the target AC circuit (30; 130; 230; 330). The method further involves controlling (74) the DC power source (12) based on the measured at least one thermal parameter to reduce a difference in power dissipation between the DC circuit (10; 110; 210; 310) and the target AC circuit (30; 130; 230; 330). The method then involves, when thermal equilibrium is reached (75), determining the power value (49) of the target AC circuit (30; 130; 230; 330) by retrieving (76) at least one real-time measurement of at least one electric parameter of the DC circuit (10; 110; 210; 310), calculating (77) a DC power value of the DC circuit (10; 110; 210; 310) based on the retrieved at least one real-time measurement of the at least one electric parameter, and calculating (78) the power value (49) of the target AC circuit (30; 130; 230; 330) using the calculated DC power value.

There is disclosed a device for determining a strength of an oscillating electric field. The device comprises an absorber to absorb radiation at the frequency of the oscillating electric field, and a thermal insulator transparent to radiation at the frequency of the oscillating electric field, which thermal insulator is arranged to thermally insulate the absorber. The device also comprises a first temperature sensor arranged to measure the temperature of the absorber, and a second temperature sensor arranged to measure the temperature external to the thermal insulator. Methods of measuring electric field using such a device, and methods of calibrating such a device, are also disclosed.

A system and method for personal energy-related changes payback evaluation with the aid of a digital computer are provided. An overall thermal performance of a building is estimated. One or more proposed replacements for existing equipment associated with an individual associated with the building is received. An annual electric consumption associated with the existing equipment is determined. The consumption associated the existing equipment is converted into a time series that includes a plurality of values that are each associated with a time interval. Renewable energy production data associated with the building is obtained. The time series is combined with the photovoltaic production data to obtain time series net consumption data. A cost associated with the time series net consumption data is determined. A payback associated with replacing the existing equipment is estimated using the cost.

A system and method for personal energy-related changes payback evaluation with the aid of a digital computer are provided. An overall thermal performance of a building is estimated. One or more proposed replacements for existing equipment associated with an individual associated with the building is received. An annual electric consumption associated with the existing equipment is determined. The consumption associated the existing equipment is converted into a time series that includes a plurality of values that are each associated with a time interval. Renewable energy production data associated with the building is obtained. The time series is combined with the photovoltaic production data to obtain time series net consumption data. A cost associated with the time series net consumption data is determined. A payback associated with replacing the existing equipment is estimated using the cost.

The overall thermal performance of a building UA.sup.Total can be empirically estimated through a short-duration controlled test. Preferably, the controlled test is performed at night during the winter. A heating source is turned off after the indoor temperature has stabilized. After an extended period, such as 12 hours, the heating source is briefly turned back on, such as for an hour, then turned off. The indoor temperature is allowed to stabilize. The energy consumed within the building during the test period is assumed to equal internal heat gains. Overall thermal performance is estimated by balancing the heat gained with the heat lost during the test period.