Use of heat pumps in HVAC systems for precise environment control in broiler houses: System's modeling and calculation of the basic design parameters

摘要

Environment control in broiler houses aims at achieving optimal growth rate and welfare conditions through ventilation, heating and cooling and is currently realized by using conventional techniques such as Liquefied Petroleum Gas (LPG) heaters, fans and evaporative panels. These systems use electricity or fossil fuels as energy sources and they are neither efficient nor renewable, thus further contribute on the increase of Greenhouse Gases (GHG) from livestock operations. They are technologies not always capable to establish optimal comfort conditions, in terms of indoor temperature and relative humidity, within the broiler house. Heat pump, on the other hand, is fully aligned with EU directive for energy efficiency and nearly Zero Energy Buildings (nZEBs) as a Renewable Energy Source (RES). The application of heat pumps as heating technology in Heating, Ventilation and Air Conditioning (HVAC) systems are capable for precise control the environment of broiler houses assuring comfortable conditions that maximize animals' welfare and productivity. This study presents a time series model to simulate in hourly step the behavior of a broiler house equipped with HVAC system with heat pump that finally concludes to the calculation of the basic design parameters of the system. The model was developed in Engineering Equation Solver (EES) model and applied for a 10,000 broilers' house at the area of Kavala in Northern Greece. Maximum grand total cooling and heating loads were estimated at 390 kW and 47 kW, respectively. The size of cooling unit should be 8 times larger than that for heating, pointing-out the major problem of high temperatures in Southeast Mediterranean. In terms of heat consumption, a year-round simulation of the broiler house reveals that sensible cooling loads account for 189 MWh while heating for 24 MWh. Sensible cooling is mostly accompanied with dehumidification and reheating, an expected finding for such dense population buildings. The model results for heating were very similar with those available from energy audits, but unfortunately no cooling data were found for comparison.