Estimating Ventilation Rates of Animal Houses through CO2 Balance

Abstract

ABSTRACT.The CO 2 production rates from various animal species were measured as well as the ventilation rates (VR) ffordable and reliable means to estimate ventilation rates (VR) of animal house is desirable for quantifying air emissions from animal operations. Traditional methods using fans or nozzles installed in the outlets of the animal house are expensive, time-consuming, and are to some extent limited to mechanically ventilated animal houses (Pedersen et al., 2008). Various alternative methods have been proposed. Pedersen et al. (1998) compared three approaches for the calculation of VR based on the balances of animal heat, moisture, and CO 2 , and they concluded that only the CO 2 balance approach is recommended for uninsulated buildings because of the difficulties in estimating the heat transmission loss from the building and in correcting for the water that evaporates from feed and wet surfaces. A sophisticated and expensive radioactive tracer gas technique has been investigated, and a good linear correlation has been reported between the results of the tracer gas technique and the CO 2 balance approach in a dairy barn (Samer et al., 2011). The CO 2 balance approach has been identified as a potential affordable alternative method to estimate VR of animal houses (Li et al., 2005;Xin et al., 2009), and it could be a viable method, especially for naturally ventilated livestock buildings, as no reliable and affordable method is currently available. However, the uncertainty of the approach is still not well understood. The CO 2 balance approach estimates VR based on the metabolic rate of animals (Van Ouwerkerk and Pedersen, 1994). The reliability of the CO 2 balance approach depends on the accuracy of the metabolic rate data of the animals and the amount of CO 2 that is not accounted for by metabolic CO 2 production, all of which requires further investigation, refinement, and validation.The CO 2 production rates from various animal species were measured as well as VR in environmental rooms at Michigan State University over the course of 15 studies. Although some of the studies have been published on topics of various dietary strategies to alter air emissions, the CO 2 production data in these studies have never been synthesized and published. The objectives of this article are to: (1) to summarize baseline data on CO 2 production rates from various animal species in these 15 studies and (2) to determine uncertainties of the CO 2 balance approach for estimating VR of animal houses by evaluating the model performance in these studies.

Quantification of methane emitted by ruminants: a review of methods

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Ventilation performance and bioenergetics of dekalb white hens in a modern aviary system

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