Heat distribution losses in ventilation heating systems

Abstract

Nowadays heat losses from hot water heating pipelines in ventilation systems are taken as zero in energy calculations in Finnish National Building Codes D3 and D5. The main aim of this bachelor thesis was to define the necessity to take those losses into account.

In order to achieve this aim two cases were examined: theoretical and practical. For both cases energy need of air handling unit (AHU) and the heat energy of heating coil were found. Then calculating of heat losses from hot water heating delivery pipelines was made. The relative amount of heat losses into the building space during heat distribution was calculated as two ratios. The first was the ratio between heat losses and heat energy of heating coil and the second ratio was between heat losses and the total energy need of AHU.

After finding the total energy need and heat delivery losses the ratio between them was found. For the theoretical case the ratio between heat losses and heat energy of heating coil is 2,5 % and the ratio was between heat losses and the total energy need of AHU equals 0,5 %. For the practical case the same ratios respectively equal 4,5 % and 2,1 %. According to the results of both cases it was concluded that the heat distribution losses from delivery pipelines of hot water heating system in energy calculations can be ignored in energy calculations.