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Method for measuring and calculating temperature and humidity of low-temperature air

A technology for temperature and humidity measurement and low-temperature air, which is applied to thermometers, measuring devices, and heat measurement, etc., which can solve the problem of precise measurement and control of the dew surface temperature of the device, the increase in the cost of high-precision dew point temperature sensors, and the inability to meet the accuracy of air humidity measurement, etc. problems, achieve automatic water replenishment, improve safety and convenience, and be easy to implement

Pending Publication Date: 2021-11-05
HEFEI GENERAL MACHINERY RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the humidity-sensitive humidity sensor method test cannot meet the air humidity measurement accuracy problem at low temperature, the air humidity parameter test using the humidity-sensitive humidity sensor method at low temperature is only used as an operating condition parameter, not as a cooling and heating capacity calculation use
[0010] With the continuous development of society, new products such as various low-temperature heat pump units can be developed and applied. Humidity sensors have poor stability and are difficult to meet the accuracy requirements of low-temperature humidity measurement, while the cost of high-precision dew point temperature sensors has increased multiples, and the device is complex and difficult to achieve precise measurement and control of the dew surface temperature

Method used

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  • Method for measuring and calculating temperature and humidity of low-temperature air
  • Method for measuring and calculating temperature and humidity of low-temperature air
  • Method for measuring and calculating temperature and humidity of low-temperature air

Examples

Experimental program
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Effect test

Embodiment 1

[0055] A device for measuring low temperature air temperature and humidity, comprising an air duct 50 and an air heater 40 that divides the air duct 50 into upstream and downstream parts. The upstream air duct is sequentially provided with a first air pressure gauge 21 and a first dry air duct along the wind flow direction. A ball thermometer 22, and together with the air duct of the upstream air duct section constitutes the sampling air measurement assembly 20; a second dry bulb thermometer 32 and an air wet bulb thermometer 33 are arranged in the downstream air duct along the wind flow direction, and are connected with The air ducts of the downstream air duct section together form the heated air measurement assembly 30 .

[0056] This low-temperature air temperature and humidity measuring device also includes an insulated box body 60 and an air sampler 10, and the insulated box body 60 sealing cover is located at the outside of the air heater 40, the heating air measuring ass...

Embodiment 2

[0067] A method for measuring and calculating low-temperature air temperature and humidity, comprising the following steps:

[0068] S1. Turn on the fan, the fan works to generate suction so that the low-temperature air enters the upstream air duct through the air sampler, and flows into the downstream air duct after being heated by the air heater;

[0069] S2. The heating air measurement component works, the fan receives the wind speed value measured by the second air manometer 31 and adjusts the operating frequency of the fan 80 to a wind speed of 5m / s±1m / s; the air heater receives the second dry bulb thermometer 32 Measured temperature results, and adjust the power of the air heater until the air temperature in the downstream air duct reaches the set temperature value;

[0070] S3. The sampled air measurement assembly 20 works, and the first air manometer 21 measures the pressure P of the sampled air before heating 1 , the first dry bulb thermometer 22 measures the air tem...

Embodiment 3

[0090] In a stable working environment 101, the air sampler 10 of the low-temperature air temperature and humidity sampling and measuring device of the present invention is placed at the air return port 100 of the machine to be tested, the fan 80 is turned on, and the measurement is performed according to the steps of Embodiment 2.

[0091] At a certain moment, the anemometer 34 measures that the current wind speed is 5m / s, and the sampled air measuring component 20 measures the pre-heating pressure P of the sampled low-temperature air 1 =100510P a , air temperature t before heating 1 =-10°C; the heated air measuring component 30 measures the air pressure P after heating 2 =100360P a , air dry bulb temperature t after heating 1 =23.4℃, wet bulb temperature t after heating w2 = 9.1°C. The sensor measurement accuracy of each dry and wet bulb thermometer used in the device is ±0.1°C.

[0092] In this embodiment, using known data, the enthalpy value h of the sampled low-temp...

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Abstract

The invention belongs to the technical field of air temperature and humidity measurement, and particularly relates to a method for measuring and calculating temperature and humidity of low-temperature air. In order to solve the problem that the wet bulb temperature of the low-temperature air is difficult to accurately and economically measure, the method realizes high-precision measurement of the wet bulb temperature and enthalpy value of the low-temperature air, the sampled low-temperature air is heated by a low-temperature air temperature and humidity measuring device through a constant-humidity reheating method, and according to the dry bulb temperature and air pressure of the sampled low-temperature air, the dry-bulb temperature, the wet-bulb temperature and the air pressure of the heated air, the temperature and humidity of the sampled low-temperature air are calculated. The method only relates to measurement of parameters of two state points, the measurement method is simple and easy to implement, the measurement precision of the low-temperature air humidity parameters is high, and integrated accurate measurement of the air temperature and humidity under the low-temperature condition can be achieved.

Description

technical field [0001] The invention belongs to the technical field of air temperature and humidity measurement, and in particular relates to a low-temperature air temperature and humidity measurement and calculation method. Background technique [0002] The ambient atmosphere we live in is a mixture of dry air and water vapor, generally referred to as humid air. Different from the concept of ambient temperature in the conventional sense, the temperature usually referred to in engineering such as drying, heating, air conditioning, and cooling towers refers to the dry bulb temperature of humid air, and this parameter can be directly measured. Generally, physical quantities such as wet bulb temperature or relative humidity and absolute humidity of the ambient atmosphere (also called "absolute moisture content") are used to characterize the humidity state parameters of humid air, so as to facilitate the analysis and calculation of the thermodynamic process of humid air in the f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01K7/02G01N27/04G01N25/68
CPCG01K7/02G01N27/04G01N25/68
Inventor 张秀平赵盼盼张欢马金平胡一清张茹吴俊峰张成王汝金
Owner HEFEI GENERAL MACHINERY RES INST