Case Analysis of a Pump-Driven Heat Pipe Heat Recovery Ventilator in an Existing Experiment Building

The building energy consumption is an important part among the total society energy consumption,in which the energy consumption for air conditioning occupies almost 70%.The energy consumption of the air conditioning system for fresh air handling can be saved effectively when the exhaust air energy could be recovered to preheat or precool the fresh air.Considering the install locations requirements on field,the pump-driven heat pipes(PHP)were developed as heat recovery ventilators(HRVs)and used in an existing experiment building in Beijing Urban.The thermal performance of the PHP HRVs was tested in real operation time periods under winter running mode.Both the power and heat consumption of the modular air handling units with and without HRVs were monitored and obtained,as well as the hourly power and heat consumption.The energy savings of HRVs were analyzed.The results indicate that the PHP HRVs can work steadily and meet the energy recovery need well.The temperature effectiveness of the HRVs can be kept from 60%to 70%.The test total energy saving rate was 24.48%,and the average hourly heat consumption reduced by 28.54%.The daily energy consumption can be saved by 118 kWh,and the energy savings can reach to 9440 kWh for a whole winter.

Efficacy of coupling heat recovery ventilation and fan coil systems in improving the indoor air quality and thermal comfort condition

Mechanical Ventilation with Heat Recovery(MVHR)systems are gaining increasing interest in buildings with low energy demand,for improvement of the Indoor Air Quality(IAQ)and reduction of the ventilation energy loss.In retrofitted buildings,MVHRs are often integrated with an additional air heater to cover space heating demand.Hence,evaluation of the interactions between MVHR and heat emitter,and their effects on indoor airflow characteristics is of significant importance.The present study aims to investigate effects of a combined MVHR-fan-coil system in heating mode on IAQ and thermal comfort parameters inside a retrofitted room,by means of a computational fluid dynamic(CFD)code.The proposed CFD model is validated by comparing the numerical results with experimental data.The results yielded by numerical simulations allow evaluating the indoor environmental quality characteristics as well as addressing the MVHR and fan coil interactions.The results indicate that the airflow discharged from the fan coil could have a significant impact on the age of the air;while it provides a desirable thermal comfort condition within the room,it may hinder to some extent delivery of the fresh air to the occupied zone due to creation of counterflow fields.Furthermore,it is shown that although increasing the fan speed(ON mode)would slightly enhance the air change efficiency,the OFF mode yields not only a better distribution of the fresh air but also a higher ventilation efficiency than when fan coil operates.