Characterization of an Air-to-Air Heat Exchanger for Manure Belt Drying Ventilation in an Aviary Laying Hen House

Abstract

SUMMARY The environment inside laying hen houses has an important effect on hen productivity, health, and well-being. Heat exchangers (HE s) can recover waste heat in ventilation exhaust to reduce supplemental heating needs while maintaining a greater fresh air exchange rate. For laying hen houses, there is limited information on the effect of heat recovery ventilation (HRV). Thus, the objective was to evaluate an air-to-air HE for manure belt drying ventilation in aviary laying hen housing. Temperature (T), relative humidity, ammonia, and manure dry matter (DM) content were characterized during a 4-wk period in October 2018. In weeks 2 and 4, the HRV was shut down and compared to weeks 1 and 3 when the HRV was operational. Average (±SD) ambient T was 10.6°C ± 4.0°C, similar for the 4-wk period. Heat exchanger efficiency was 75.07% ± 9.4% with the average supply temperature increased by 10.0°C ± 3.4°C and an average of 93.94 ± 31 kW heat recovered. Average indoor T (23.1°C ± 0.5°C) was warmer as a function ambient T and daily average T range was lower with HRV (1.8°C ± 0.7°C) compared to without HRV (22.2°C ± 1.2°C; 3.1°C ± 1.1°C). Seven days after manure removal, final average manure DM was 40.6% ± 3.1% (without HRV) and 60.0% ± 3.3% (with HRV). Implementation of HRV positively influenced indoor thermal environment by maintaining less dynamic diurnal fluctuations and greater temporal T uniformity.