Abstract
A microcontroller based, thermal energy meter cum controller (TEMC) suitable for solar thermal systems has been developed. It monitors solar radiation, ambient temperature, fluid flow rate, and temperature of fluid at various locations of the system and computes the energy transfer rate. It also controls the operation of the fluid-circulating pump depending on the temperature difference across the solar collector field. The accuracy of energy measurement is ±1.5%. The instrument has been tested in a solar water heating system. Its operation became automatic with savings in electrical energy consumption of pump by 30% on cloudy days.

1 Introduction
Solar water heating systems find wide applications in industry to conserve fossil fuel like oil, coal etc. They employ motor driven pumps for circulating water with on-off controllers and calls for automatic operation. Reliability and performance of the system depend on the instrumentation and controls employed. Multi-channel temperature recorders, flow meters, thermal energy meters are the essential instruments for monitoring and eva luating the performance of these systems. A differential temperature controller (DTC) is required in a solar water heating system for an automatic and efficient operation of the system. To meet all these requirements, a microcontroller based instrument was developed. Shoji Kusui and Tetsuo Nagai [1] developed an electronic heat meter for measuring thermal energy using thermistors as temperature sensors and turbine flow meter as flow sensor.

摘 要
適用于太陽能熱系統(tǒng)的單片機熱能表控制器（TEMC）已經(jīng)研制成功。它能夠監(jiān)測太陽輻射，空氣溫度，流體速度，在不同地點系統(tǒng)的流體溫度和計算能量的傳輸速率。它也能根據(jù)全國太陽能極熱地的溫差來控制流體循環(huán)泵的操作。電能計量準確度為± 1.5％。該儀器已經(jīng)過太陽能供熱水系統(tǒng)的測試。陰天自動調(diào)到節(jié)能模式節(jié)能70％。

1 緒 論
太陽能熱水系統(tǒng)在工業(yè)上有著廣泛的應用，因為它能節(jié)約化石燃料如石油，煤炭等。使用電機驅(qū)動泵和開關(guān)控制器自動循環(huán)水源。系統(tǒng)的性能和可靠性依賴于儀器的精度和控制。多通道溫度記錄儀，流量計，熱能表，負責監(jiān)察和評估這些系統(tǒng)性能的重要手段。溫差控制器（DTC）是一種能夠自動高效的運作太陽能熱水系統(tǒng)的控制器。為了滿足所有這些要求，基于微控制器的儀器已經(jīng)開發(fā)。Shoji Kusui和Tetsuo Nagai發(fā)明了一種電子熱能表，用于測量熱能。這種表使用了熱敏電阻和作為流量傳感器的渦輪流量計。