HRP20181196A2 - System for detecting air congestion of fan coil unit heat exchanger - Google Patents

Abstract

This application describes a system for detecting partial or complete air clogging of a fan coil heat exchanger. It is crucial to use the information on the return temperature of the heat exchanger (11) of the fan coil (8). Two detection algorithms are listed, one that can only detect complete blockage and requires very little information about the system and the other that can detect both complete and partial blockage and requires more detailed models of correct fan coil units. air congestion of fan coil unit heat exchanger is described. Hereby, it is essential to use information on temperature of heat exchanger return duct (11) of the fan coil unit (8). Two detection algorithms are given, one that detects only complete congestion and requires very little information about the system and the other that can detect both total and partial congestion and requires more detailed models of correct fan coil units.

Description

Technical field to which the invention relates

This invention relates to a system that enables the detection of air blockage of fan coil heat exchangers, their remote monitoring in this sense, and thus efficient maintenance of the heating and cooling system that relies on fan coil units in the premises of the building.

Technical problem

When a certain amount of air enters the heating or cooling installations, the normal flow of the heating or cooling medium through the heat exchanger in the valve convector is prevented or this flow is completely stopped. The entry of air into the system occurs during interventions on the medium supply/drainage pipeline to/from individual fan convectors or a specific floor group of devices, and often when changing the regime from heating to cooling or vice versa when the system configuration or heat source/sink is changed. Until now, when removing air from the system, building maintenance personnel have had to visit all fan coil units, during which they manually check for the presence of air with appropriate valves and, if necessary, carry out venting.

In this case, the maintenance service staff usually comes at the request of users of rooms whose comfort has been previously impaired, since heating/cooling with the fan coil is not possible when the heat exchanger of the fan coil is blocked, and thus the productivity of the users themselves is impaired.

State of the art

A relevant work for the state of the art is the work of Pourarian et al. A tool for evaluating fault detection and diagnostic methods for fancoil units, Energy and Buildings, 136 (2017) 151-160, which presents a method of error detection in the operation of fan coil units based on the comparison of room temperature response and control variables of the fan coil unit. The method in this paper requires knowledge of the reference model of the room itself and complex detection based on recorded time profiles of room temperature and control variables of the fan coil unit itself.

Presentation of the essence of the invention and a detailed description of at least one way of realizing the invention

It is assumed that the fan coil units (8) are placed in parallel, where each one is connected to the supply (9) and drain (10) pipe of the heating/cooling medium (Figure 1). The fan coil error detection system consists of: one medium flow temperature sensor on the incoming pipe (1) which is common to the entire group of fan coil units that are fed behind the place where the sensor is installed, one sensor of the total flow of the medium on the incoming pipe (2), a sensor the temperature of the return medium (3) mounted at the end of the heat exchanger (11) in each fan coil unit (Figure 2), the usual control device for the fan coil unit (4) which regulates the temperature of the room, and from which it is possible to obtain information about the rotation speed of the fan coil unit and the temperature of the room , the communication system (5) which collects measurements from the temperature sensors on the pipes and from the control device connected to the fan coil unit, data on the rotation speed of the fan coil unit and the air temperature of the room where the fan coil unit is located, the database (6) where the said measurements and data are stored and computer applications (7) in which the implem completes the algorithm for detecting faulty operation of fan coil units using measured temperatures, measured flow and data on fan rotation speed of individual fan coil units.

The algorithm in the mentioned application for the detection of air blockage can function in a way (I) that it does not use any model of the fan coil unit, whereby it is possible to detect a complete blockage of the fan coil unit with air, or (II) that it uses a predetermined model of the fan coil unit and the fan coil unit distribution, in which case it is possible to determine and degree of clogging of all fan convectors with air.

The algorithm is applicable for the case when the temperature of the starting medium is higher than 303.15 K, which is a regular situation during the heating process, or when it is lower than 293.15 K, which is a regular situation during the cooling process. If the incoming medium is in the temperature range [293.15, 303.15] K, it is assumed that it is an inactive system, and then detection is not possible.

In the case of heating or cooling, by comparing the detected temperature of the starting medium with the limit values of at least 303.15 K for heating or at most 293.15 K for cooling in mode (I), clogging of the fan coil unit with air is detected if, with the fan coil unit fan turned off, the measured temperature of the return medium corresponds to the room temperature. In the case of heating or cooling in mode (II), the clogging coefficients of each individual fan coil unit are determined by applying an estimation procedure, whereby the best set of values of these coefficients is determined in the continuous operation of the fan coil unit so that the behavior of the measured temperature of the return media of individual fan coil units corresponds as closely as possible to the behavior of the model of the fan coil unit with the introduced clogging coefficients.

Brief description of the drawing

Figure 1 shows a typical configuration of the pipeline and fan coil system associated with that pipeline to which the invention relates, with the basic sensor elements highlighted and the communication system and database sketched.

Figure 2 shows an enlarged view of the installation location of the temperature sensor of the return medium from the fan convector.

(1) temperature sensor

(2) flow sensor

(3) temperature sensor

(4) control device

(5) communication system

(6) database

(7) computer application

(8) fan convector

(9) incoming pipe

(10) return pipe

(11) heat exchanger

Claims (2)

1. System for detecting air clogging of the fan coil heat exchanger on the part of the building's heating or cooling system, which consists of a common incoming (9) and return pipe (10) for the supply and discharge of the heating or cooling medium and the fan coil (8) or group of fan coils ( 8) connected in parallel to the supply and return pipes, whereby this detection system consists of: one medium temperature sensor on the incoming pipe (1) which is common to the entire group of fan coil units, a return medium temperature sensor (3) mounted at the end of the exchanger of heat in each fan coil unit, the usual control device for the fan coil unit (4) which regulates the temperature of the room, and from which it is possible to obtain information about the status of the fan coil unit fan and the room temperature, the communication system (5) which collects measurements from the temperature sensors on the pipes and from the control unit of the device connected to the fan convector, data on sta the inclusion of the fan of the fan coil and the air temperature of the room where the fan coil is located, and the database (6) where the above measurements and data are stored, and is characterized by the fact that it uses a computer application (7) in which the algorithm for detecting faulty operation of the fan coil is implemented using the measured temperature and data on the status of the fans of individual fan coil units in such a way as to detect complete clogging of the fan coil unit with air when the temperature of the supply medium is greater than 303.15 K in the case of heating or less than 293.15 K in the case of cooling, and when the fan coil unit fan is turned off, the measured temperature of the return medium corresponds to room temperature temperature. 2. System for detecting air clogging of the fan coil heat exchanger on the part of the heating or cooling system of the building, which consists of a common inlet (9) and return pipe (10) for the supply and discharge of the heating or cooling media and the fan coil (8) or group of fan coils ( 8) connected in parallel to the supply and return pipes, whereby this detection system consists of: one sensor of the supply temperature of the medium on the incoming pipe (1) which is common to the entire group of fan coil units, one sensor of the total flow of the medium on the incoming pipe (2) , the temperature sensor of the return medium (3) mounted at the end of the heat exchanger in each fan coil unit, the usual control device for the fan coil unit (4) which regulates the temperature of the room, and from which it is possible to obtain information about the rotation speed of the fan coil unit and the temperature of the room, the communication system (5 ) which collects measurements from temperature sensors on the pipes and manages them of the device connected to the fan coil unit, data on the rotation speed of the fan coil unit and the air temperature of the room where the fan coil unit is located, and the database (6) where the measurements and data are stored, and is characterized by the fact that it uses a computer application (7) in which it is implemented an algorithm for detecting malfunctioning fan coil units using measured temperatures, measured flow and data on fan rotation speed of individual fan coil units in such a way as to detect both partial and complete clogging of the fan coil unit with air so that it joins the coefficients of the clogging of the fan coil unit, and these are determined by applying an estimation procedure based on the method least squares, whereby the best set of values of these coefficients is determined in the continuous operation of the fan coil units so that the behavior of the measured temperatures of the return medium of individual fan coil units corresponds as closely as possible to the behavior of the nominal models of the specific fan coil units in normal operation, with introduced clogging coefficients, whereby the nominal fan coil models are determined by applying estimation procedures over historical data recorded in the mode of operation in which all fan coils are working.