Cooling metering system for chilled water
1. Overview
With the increase of large buildings and modern buildings, the cooling system has achieved rapid development, and the demand for cooling capacity in industry and its chemical industry has also promoted the development of central cooling. Central cooling is the cold medium (generally fresh water and salt water) used by the power plant to supply the cooling capacity of the freezer to the user. In order to manage and account for the operation of refrigeration equipment and settle the cooling consumption of users, it is necessary to measure the cooling capacity of relevant nodes.
As far as the method of cooling measurement of frozen water is concerned, it is the same as the heat measurement of hot water, and the cooling volume supplied can be regarded as negative heat. However, due to the low temperature of the fluid, there are some differences in specific practices.
2. Schematic diagram of the installation of the cooling metering system of refrigerated water
The water temperature level of chilled water for air conditioning is generally 5-6°C, and the cold medium is fresh water. For cooling below 5°C, use salt water or other cold media. The cooling measurement method of freshwater frozen water mostly adopts the mass flow-based measurement method as shown in the figure below.
(1) In the flow measurement of chilled water, LD electromagnetic flowmeter has obvious advantages, and its characteristics are as follows:
◆ 电磁流量计测量不受流体密度、粘度、温度、压力和电导率变化的影响。
◆ 电磁流量计测量管无阻碍流动部件、无压损、直管段要求较低。
◆ 电磁流量计传感器可带接地电极，实现仪表良好接地。
◆ 电磁流量计传感器采用先进加工工艺，使仪表具有良好的抗负压能力
(1) Lining selection of LD series electromagnetic flowmeter: if the chilled water is freshwater, you can choose the rubber liner, the cost is lower, if the chilled water is salt water, you must choose the PTFE liner, if you measure both freshwater frozen water and salt water, you must choose the PTFE liner, the FLDC electromagnetic flowmeter produced by Nankong Instrument can choose the appropriate lining material according to the situation on site.
(2) The selection of thermal resistance, Nankong Instrument adopts high-quality, high-precision A-class armored thermal resistors, with an accuracy of up to ±0.2%, which greatly improves the accuracy of the system.
(3) XSR22 series heat accumulator for on-site temperature, flow and other signals for collection, display, control, remote transmission, communication, printing and other processing, constituting a digital acquisition system and control system, suitable for heat transfer oil boiler, plumbing and other heating systems and heat exchange systems, air conditioning cooling and heat measurement of units, buildings and heat exchange stations and heat company pipe networks, to achieve online measurement of heat transfer and mass transfer, so as to provide a basis for enterprise energy management, energy consumption measurement, technical economy.
(2) In addition to the measurement of the electromagnetic flowmeter, the TUF series ultrasonic flowmeter can also be used to measure, customers can choose according to the site situation, the installation diagram of the ultrasonic flowmeter thermal energy metering system is shown below.
(1) TUP series ultrasonic flowmeter adopts the international standard thermal enthalpy value caloric calculation formula (enthalpy difference method) to realize the measurement of cooling/heat, in order to meet the needs of users under different working conditions, it can be divided into integrated type, split type, suitable for cooling heat of air conditioning and heat measurement of units, buildings and heat exchange stations and heat company pipe network, etc.
(2) The selection of thermal resistance, Nankong Instrument adopts high-quality, high-precision A-class armored thermal resistors, with an accuracy of up to ±0.2%, which greatly improves the accuracy of the system.
Schematic diagram of the installation of TUF series integrated ultrasonic flowmeter thermal energy metering system
Installation diagram of FLCB-G series pipeline ultrasonic flowmeter heat metering system
