Mathematical simulations of air-to-air heat pump brooding for broilers.

摘要

Two mathematical models were developed in this study: (1) HACLM, was developed to describe the performance of 20,000 broilers raised in floor operations, and (2) HEATP, was developed to predict the performance of different sizes of air-to-air heat pumps.; The models were used to determine the economic value of heat pumps for rearing broilers. The value of cooling to relieve mortality due to heat stress was included in the assessment. It was hypothesized that the dual benefits of the heat pump for brooding and for cooling may make the heat pump a more viable economic choice.; Ten years of weather data from 1968 to 1977 for Salisbury, Maryland, were used in the models. An insulated broiler house of a size common for Maryland was used in the model simulations.; The peak heat load varied from year to year averaging 45 kW over the ten year period. It occurred in the first week of bird production in January flocks. No heat was required after the fourth week. In summer, the maximum cooling load was 77 kW in July flocks and was required near market age. The HEATP switched from "heating mode" to "cooling mode" to describe the performance in summer.; Three different sizes of heat pumps, 61.53 kW (17.5 ton), 82.63 kW (23.5 ton), and 94.93 kW (27 ton) were compared. Based upon the total energy costs, the 61.53 kW capillary tube heat pump was projected as the most economical size to heat the 20,000 chicken house. It was slightly undersized for cooling but the length and degree of the lapse in temperature control was considered acceptable.; The total costs, cents/bird marketed, of heating were 4.331 and 3.919, respectively, for the heat pump and LP gas in a January flock. The total annualized cost of the 61.53 kW air conditioner was 7.465 cents/bird marketed in a July flock.