Abstract:
The overall thermal performance of a building UATotal 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.
Abstract:
A method and an arrangement are provided in connection with a photovoltaic power generator composed of series-connected photovoltaic modules. The method includes determining a maximum power point voltage (UMPP) and a maximum power point current (IMPP). The method also includes determining the ambient temperature (Tamb), calculating an estimated maximum power point voltage (Uest) by using maximum power point current (IMPP) and the determined ambient temperature (Tamb), comparing the estimated maximum power point voltage with the determined maximum power point (UMPP), and determining on the basis of the comparison whether the generator is operating under uniform conditions or in conditions with two maximum power points.
Abstract:
Methods, systems, and devices for determining a power flow are described herein. One method includes determining a temperature of a circuit conductor while the circuit conductor is conducting a current, and determining a power flow associated with the circuit conductor based, at least in part, on the determined temperature.
Abstract:
A power measurement transducer includes a thermally conductive heat spreading device having a first surface configured to thermally couple the power measurement transducer to a device under test. Two or more temperature measurement elements are positioned within the thermally conductive heat spreading device.
Abstract:
A method of determining thermal output of a device under test includes attaching a power measurement transducer to a device under test, wherein the power measurement transducer includes two or more temperature measurement elements. A test sequence is applied to the device under test. One or more signals produced by the power measurement transducer are monitored to determine a quantity of power produced by the device under test during the test sequence.
Abstract:
A sensor comprises a reference sample arranged to be subject to at least one variable physical parameter such that a variation in the value of the at least one variable physical parameter causes a change in the magnetisation of the reference sample, means for measuring the magnetisation of the reference sample, and means for determining in dependence upon the measured magnetisation whether there has been a variation in the value of the at least one variable physical parameter, wherein the reference sample comprises a Heusler alloy.
Abstract:
A circuit for sensing radio frequency energy. The circuit includes a Wheatstone bridge having at least one element thereof thermally responsive to the radio frequency energy passing therethough differently from radio frequency energy passing though at least one other element of the bridge.
Abstract:
The invention concerns a sensor for direct measurement of electromagnetic power, comprising a guiding structure (2) for bringing the power, a dissipative charge (3) and a thermometer. The invention is characterized in that the charge (3) and the thermometer are formed by a single element.
Abstract:
An apparatus is disclosed which accurately measures, over a wide ambient temperature range, the average power derived from an electrical signal. Furthermore, embodiments of the present invention can be fabricated with inexpensive, off-the-shelf components and can have excellent circuit characteristics at RF frequencies. These results are obtained in an illustrative embodiment of the present invention that comprises a first thermal detector, a second thermal detector, an error amplifier and a summer. The first thermal detector provides a reference signal, which varies with the ambient temperature, to the error amplifier. The summer receives the signal to be measured and the signal output from the error amplifier, and outputs to the second thermal detector a composite signal, which is indicative of the sum of the power derived from input signal and the output signal from the error amplifier. The second thermal detector receives the composite signal and outputs a feedback signal, which is indicative of power derived from the composite signal, to the error amplifier. The output signal, which is indicative of the power derived from the input signal, is the output of the error amplifier. The error amplifier advantageously subtracts the feedback signal from the reference signal, and advantageously outputs the amplified difference to the summer.
Abstract:
A solar energy flux integrator includes a semiconducting solar cell positioned to receive solar radiation, and a micro-coulombmeter connected to receive current from the solar cell. The micro-coulombmeter comprises a glass capillary filled with a mercury salt electrolyte having an indicating bubble and two mercury electrodes. A series resistor is provided which has a resistance value to slow the movement of the bubble when low levels of solar energy are incident on the cell so that movement of the bubble is directly proportional to the incident solar flux. This series resistor compensates for the spectral shift towards blue of the indirectly received solar radiation, which spectral shift otherwise causes the measured integrated value of solar flux to be too high due to the greater sensitivity of the solar cell to light of shorter wavelengths. A parallel resistor is provided to scale the output of the solar cell to the Micro-Coulombmeter and a reversing switch is connected to permit travel of the indicating bubble in opposite directions.