毕业设计英文翻译

毕设中英文翻译

外文资料与中文翻译

外文资料：

Intelligent thermal energy meter controller

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 evaluating 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.

2 Instrument details

The block diagram of the microcontroller (Intel 80C31) based thermal energy meter cum controller is shown in Fig. 1. RTD (PT100, 4-wire) sensors are used for the temperature measurement of water at the collector field inlet, outlet and in the tank with appropriate signal conditioners designed with low-drift operational amplifiers. A precision semiconductor temperature sensor (LM335) is used for ambient temperature measurement. A pyranometer, having an output voltage of 8.33 mV/kW/m2, is used for measuring the incident solar radiation. To monitor the circulating fluid pressure, a sensor with 4–20 mA output is used. This output is converted into voltage using an I-V converter. All these output signals are fed to an 8-channel analog multiplexer (CD4051). Its output is fed to a dual-slope 12-bit A/D converter (ICL7109). It is controlled by the microcontroller through the Programmable Peripheral Interface (PPI-82C55).

Fig. 1. Block diagram of thermal energy meter cum controller.

A flow sensor (turbine type) is used with a signal conditioner to measure the flow rate. Its output is fed to the counter input of the microcontroller. It is programmed to monitor all the multiplexed signals every minute, compute the temperature difference, energy transfer rate and integrated energy. A real-time clock with MM58167 is interfaced to the microcontroller to time-stamp the logged data. An analog output (0–2 V) is provided