Types of Temperature Sensors

There are three main types of temperature sensors: thermometers, resistance temperature detectors and thermocouples. These sensors measure a physical property that changes as a function of temperature, and temperature sensors are classified into contact and non-contact sensors. Contact sensors detect the degree of hotness or coldness of an object when placed in direct contact with the object. It can be used to sense the degree of hotness or coldness in liquids, solids or gases in a wide range of temperatures. Contact temperature sensors include thermometers, thermocouples and thermistors. A thermometer detects the body temperature of human beings, and a thermocouple is a thermoelectrical thermometer that works on the principle of the Seebeck effect; they are cheap; hence, their model and basic materials are easy to get, and non-contact sensors are not placed in contact with the object that it measures; however, they measure the temperature by utilizing the radiation of the heat source. IR sensors detect the energy of an object remotely and emit a sign to an electronic circuit that senses the object’s temperature by a specific calibration diagram. Other types of temperature sensors are available and produced based on the working principle, size, temperature range and their function and application

Figures of Merit for Wind and Solar PV Integration in Electricity Grids

349-357In future electrical grids, high levels of Variable Renewable Energy (VRE) penetration including solar photovoltaics (PV) and wind energy is expected. This poses a challenge in system operation and planning especially in balancing electricity demand and supply. This paper examines figures of merit for wind and solar integration in electricity grids. Quantitative tools such as load duration curves, correlation analyses, and the Fourier transform were used to study the intermittency/variability of wind and solar PV power. Time series data on power production from the European Network of Transmission System Operators for Electricity (ENTSO-E), and Réseau de Transport d'Électricité (RTE) were used for the analyses. The analyses illustrate that despite the valuable amount of energy that can be obtained from wind and solar PV, these energy sources cannot be used as baseload power supply. Solar PV power is available for approximately 50% of the time year-round. Wind power output on the other hand can reach very small magnitudes of just a few megawatts several times in a year. More to that, wind is positively correlated over long distances, even exceeding 3000 km and aggregating wind fleets over a large geographic area might not guarantee continuous availability of wind power. Nonetheless, these sources can still be integrated in electricity grids in high proportions, provided intermittency mitigation options such as energy storage, curtailment, and demand-response are implemented

Figures of Merit for Wind and Solar PV Integration in Electricity Grids

In future electrical grids, high levels of Variable Renewable Energy (VRE) penetration including solar photovoltaics (PV) and wind energy is expected. This poses a challenge in system operation and planning especially in balancing electricity demand and supply. This paper examines figures of merit for wind and solar integration in electricity grids. Quantitative tools such as load duration curves, correlation analyses, and the Fourier transform were used to study the intermittency/variability of wind and solar PV power. Time series data on power production from the European Network of Transmission System Operators for Electricity (ENTSO-E), and Réseau de Transport d'Électricité (RTE) were used for the analyses. The analyses illustrate that despite the valuable amount of energy that can be obtained from wind and solar PV, these energy sources cannot be used as baseload power supply. Solar PV power is available for approximately 50% of the time year-round. Wind power output on the other hand can reach very small magnitudes of just a few megawatts several times in a year. More to that, wind is positively correlated over long distances, even exceeding 3000 km and aggregating wind fleets over a large geographic area might not guarantee continuous availability of wind power. Nonetheless, these sources can still be integrated in electricity grids in high proportions, provided intermittency mitigation options such as energy storage, curtailment, and demand-response are implemented