Demidochkin V.V., Kostuganov A.B., Cherchayev A.A.
DETERMINATION OF HEAT TECHNICAL EFFICIENCY OF LAMINATED HEAT RECOVER ^{[№ 6 ' 2018]}
In modern civilian buildings the quality of indoor air is often lower than standard indicators and this fact leads to the manifestations of the “sick building syndrome”. Also, ventilation systems of civilian buildings occupy the third place in the amount of energy consumed among engineering systems and are one of the priority areas for optimizing energy consumption. Factors to increase the efficiency of use of energy consumed and to improve the quality of indoor air indicators in buildings require the use of modern solutions that enhance the efficiency of ventilation systems. The use of air heat exchangers is the most obvious technical measure contributing to the solution of this problem. However, as a result of our literary sources review was established that today the issues of determining the real operational efficiency of these devices, as well as the organization of their protection against freezing, are not well studied.
We have conducted experimental studies to study the temperature field of the air flow of a cross plate heat exchanger, as well as studies aimed at determining the efficiency of this heat exchanger in several operating modes. As a result of our studies a pronounced temperature stratification of the air flow after the heat exchanger was revealed, the positions of the measuring sections for installing temperature sensors was determined and the efficiency values in several operating modes was calculated. Based on the results of our study, we determined that the thermal efficiency of such heat exchanger varies from 62 to 71 %, and the temperature efficiency is from 52 to 59 % at a flow velocity in the range from 1.5 to 6.2 m/s.
We have founded that the temperature field of the air flow significantly depends on the design of the heat exchanger and remains similar for the main operating range of speeds and air flow rates. We have also confirmed experimentally the value of the temperature efficiency of the heat exchanger of this type at 55 % for the main practically encountered in ventilation systems the air flow velocity in the range of 1.5—5 m/s.