air-to-air heat exchanger

When considering the performance of HRV systems, the discussion is generally focusing on the reported effectiveness of the air-to-air heat exchanger. Although some excellent presentations at the AIVC conference in the past have dealt with uncertainties related to the test of that effectiveness, the fact that the heat recovered by the HRV unit might not be useful in an intermittently heated dwelling without room-by-room based demand control is usually not considered. Therefore, the ‘use-factor’ for the recovered heat is quantified in this paper.

In the frame of the European project called Bricker, a new prototype of single room ventilation with heat recovery has been developed. This new unit is supposed to be installed in class rooms of an educational institution. This paper deals with the development of the first prototype of this unit. An empirical model of such device is also proposed in order to be coupled with a building model. This aims at determining the seasonal performance of the device and thus the potential energy saving (compared to other technologies) resulting from its use.

Nowadays, important efforts are made to reduce the residential building energy consumption. In this context, a growing interest for heat recovery ventilation has been observed during the last decades. The present paper focuses on a new single room ventilation with heat recovery. Double flow ventilation is achieved through the integration of the unit into windows ledges. The developed device is particularly suitable compared to traditional centralized heat recovery ventilation units for retrofitted houses due to the absence of air extracting and air pulsing ducts through the house. 

Using performance characteristics of balanced ventilation units tested in laboratory of CETIAT, a complete ventilation system in an individual house is modelised, in details. Simulations are made with TRNSYS program and hourly dynamic calculations on the heating season, on different French climates (three) and different ventilation configurations (five) : high efficiency or classical balanced system inside the attic or inside the heated volume and simple exhaust ventilation system.

This article discusses how to integrate all air-to-air devices into an HVAC system that may contain one or more air-to-air exchangers as well as conventional components for ventilation and comfort control.HVAC systems with air-to-air exchangers need to be carefully designed for the location of each device in the system, with the winter and summer design performance of each device and the total annual energy saved by the HVAC system.