PRINCIPLES AND PRACTICES TO INCREASE VENTILATION SUCCESS

Transcription

1 PRINCIPLES AND PRACTICES TO INCREASE VENTILATION SUCCESS Steven J. Hoff, PhD PE and Brett C. Ramirez Department of Iowa State University, Ames, IA, USA June 30 th, Iowa Swine Day

2 Agenda Air leakage rates of swine finishing facilities Understanding how animals exchange heat Quantifying the thermal environment Combining measurements to predict thermal environment Practical applications of new technology 2

3 Infiltration rates of swine finishing facilities 3

4 Infiltration (air leakage) rates were measured following a standard procedure to identify which components of the building leaked the most. Inclined manometer for static pressure measurement 54 and 36 FANS units for airflow measurement 4

5 Four sources of infiltration were quantified: 1) As-is or total infiltration (primary inlets sealed) 2) Curtain infiltration (curtain top, end-pockets) 3) Fan infiltration (sidewall fans, pit fans, pump-out covers) 4) Other infiltration (doors, ceiling, ceiling/wall joints, etc.) 5

6 18 rooms housed in four different building construction types were tested. Range of room characteristics: Length: 124 to 237 ft Width: 40 to 60 ft Age: 2 to 23 years old 1) Single 2) Double wide 3) Double wide + H-Type 4) H-Type 6

7 As-is leakage for all 18 finishing rooms tested. Infiltration rate, ACH single barns double-wide barns H-type barns double-wide+h-type barns Static pressure across room, Pa 7

8 Comparison of As-is versus Other infiltration rates: 8

9 Infiltration rate comparison at ΔP = 0.08 in. wc by room and infiltration source: Infiltration rate, ACH As is leakage Curtain leakage Fan leakage Other leakage Room Number 9

10 Predicted infiltration rate summary (ACH): Infiltration Rate, ACH Pa 20 Pa 30 Pa IA IC IF IO Infiltration Type P=10 Pa P=20 Pa P=30 Pa I A I O I A I O I A I O Average SD Maximum Minimum Median

11 Infiltration study summary (at ΔP = 0.08 in. wc): As-is leakage rate = 6.43 ± 1.68 ACH Curtain leakage rate = 1.47 ± 0.71 ACH (23%) Fan leakage rate = 1.63 ± 0.77 ACH (25%) Other leakage rate = 3.33 ± 1.23 ACH (52%) The Challenge: identify other sources of infiltration and develop practical low-cost retrofit solutions. 11

12 So, what does it all mean As-is leakage rate for five newly constructed (tight) swine barns = 1.4 ACH at P = 20 Pa (Zhang and Barber, 1995) As-is leakage rate for commercial broiler houses = 3.6 to 5.6 ACH at P = 25 Pa (Lopes et al., 2010) Minimum winter ventilation required in swine finishing = 2 to 10 ACH for pigs between 6 to 115 kg (MWPS, 1987) 12

13 Thermal exchange and animal response 13

14 SURVIVAL ZONE (death occurs below or above this core body temperature zone) HOMEOTHERMY ZONE (normal core body temperature zone) THERMONEUTRAL ZONE (minimal effort) COMFORT ZONE Feed Intake Increased vasoconstriction, piloerection, behavioral changes, shivering Regulation by vaso-modification, pilomodificaiton, behavioral changes Increased vasodilation, water intake, panting, behavioral changes Core Body Temperature Heat Production (metabolism) Effective Environment Goal of Ventilation System Adapted from Kerr, 2015 (Washington State University Fact Sheet - FS157E) 14

15 There are four modes of thermal energy exchange between an animal and its surroundings inside a building. Natural convection Evaporation Forced convection Radiation Conduction 15

16 Animals generate heat due to many processes and strive to maintain their body temperature at a near-constant level. Basal Metabolism Obtaining Nutrients Heat Increment Heat Combating Stresses Poor Environment Constant core temperature 16

17 When the ventilation system is unable to remove the optimum amount of heat, the animal responds with physiological and behavioral changes. Reduced Feed Intake Reduced Growth Performance Huddling, wallowing, separation Mortality 17

18 Heat (thermal energy) generated by the animal must equal the environments thermal capacity to remove that heat. Q convection + Q evaporation + Q radiaiton + Q conduction = Heat Production Natural convection Evaporation Forced convection Heat Production Radiation Conduction 18

19 To assess if the ventilation system is removing the optimum amount of amount of heat, we developed the Capacity to Dissipate Heat (CDH) index. Q convection + Q evaporation + Q radiaiton + Q conduction Optimum Heat Production = CDH Feed Intake Core Body Temperature Increasing capacity (heat removed faster than generation rate) Heat Production (metabolism) Capacity to Dissipate Heat from the Animal Decreasing capacity (internal heat accumulates) 19

20 Measuring thermal exchange 20

21 The four measurable parameters to estimate the thermal capacity of the environment are: Dry-bulb Temperature Dry-bulb Temperature & Relative Humidity Dry-bulb Temperature & Airspeed Mean Radiant Temperature Neglected 21

22 These have been combined into a cost-effective, robust thermal environment sensor array (TESA) t db RH t mr t g Airspeed 22

23 Each TESA can be connected and distributed throughout a room for spatial and temporal data collection with minimal maintenance. 23

24 Example of current installation of six TESAs 24

25 Practical uses of the thermal environment sensor array 25

26 Heat stress currently causes major economic and production losses in the US swine industry. Overall Estimated $316 to $330 million annual losses Boars 3 days of exposure to >85 F caused drastic increase in abnormal sperm per ejaculate, with ~8 weeks for recovery RH >75% in combination with 79 F to 85 F showed gradual increase in abnormal sperm per ejaculate with about ~6-8 weeks for recovery Sows 789 average hours per year exposed to heat stress 5.2 day average increase in sow open days Smaller litters and lighter weaning weights Growing to Finishing 1010 average hours per year exposed to heat stress Lower feed intake, weight gain, and feed efficiency 26

27 Heat stress alleviation: current sprinkler control systems operate at a fixed interval regardless if the applied water evaporates. 27

28 An intelligent sprinkler control system changes the off interval to account for the different water evaporation rates to minimize water usage. 28

29 One application specifically for boar studs with a custom designed nozzle and stir fan. 29

30 Water usage and time heat stressed estimated for conventional and intelligent sprinkler control systems were compared using July and August 2015 data. 30

31 Commissioning: develop functional performance testing to evaluate the effectiveness of a facilities ventilation and control system Fan Performance Inlet Distribu,on Commissioning Func,onal Performance Tes,ng Controller Capability Heater Distribu,on Animal Zone Comfort Thermal Stress Assessment 31

32 Our approach to measuring the spatial distribution of the thermal environment over time through different seasons. 32

33 With this data, the thermal environment uniformity can be analyzed; then adjustments to the ventilation system can be made to improve performance. 33

34 The ultimate goals are: Improve our understanding of the different ways pigs lose heat Use TESA as feed back to control barn temperature Replace traditional temperature sensors with TESA Develop a standardized procedure to commission new and existing facilities 34

35 Thank you! Questions? Dr. Steve Hoff, Brett Ramirez, 35

36 References ASHRAE. (2013). Handbook of fundamentals. Atlanta, GA: America Society of Heating, Refrigeration and Air Conditioning Engineers. Brown-Brandl, T., Hayes, M., Xin, H., Nienaber, J., Li, H., Eigenberg, R. A., Shepard, T. (2014). Heat and Moisture Production of Modern Swine. ASHRAE Transactions, 120. Curtis, S. E. (1983). Environmental Management in Animal Agriculture. Ames, IA: The Iowa State University Press. DeShazer, J. A. (2009). Livestock Energetics and Thermal Environmental Management (1st ed.). St. Joseph, MI: American Society of Agricultural and Biological Engineers. Flowers, W. (2015). Factors Affecting the Efficient Production of Boar Sperm. Reproduction in Domestic Animals, 50, Gao, Y., Ramirez, B. C., & Hoff, S. J. (2016). Omnidirectional thermal anemometer for low airspeed and multi-point measurement applications. Computers and Electronics in Agriculture. Kerr, S. (2015). Livestock Heat Stress: Recognition, Response, and Prevention (Extension Fact Sheet No. FS157E). Washington State University. McNitt, J. I., & First, N. L. (1970). Effects of 72 hour heat stress on semen quality in boars. International Journal of Biometeorology, 14(4), Pollman, D. S. (2010). Seasonal effects on sow herds: Industry experience and management strategies. Journal of Animal Science, 88((Suppl. 3):9). Ramirez, B. C., Hoff, S. J., Gao, Y., & Harmon, J. D. (2016). Development and Validation of a Spatial and Temporal Thermal Environment Sensor Array and Data Acquisition System. In 2016 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers. Ramirez, B. C., Hoff, S. J., Gao, Y., & Harmon, J. D. (2015). Commissioning of a novel animal thermal environment replication and measurement system. In 2015 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers. Rhoads, R. P., Baumgard, L. H., Suagee, J. K., & Sanders, S. R. (2013). Nutritional Interventions to Alleviate the Negative Consequences of Heat Stress. Advances in Nutrition: An International Review Journal, 4(3), St-Pierre, N. R., Cobanov, B., & Schnitkey, G. (2003). Economic Losses from Heat Stress by US Livestock Industries. Journal of Dairy Science, 86, Supplement, E52 E77. Suriyasomboon, A. (2005). Herd investigations on sperm production in boars, and sow fertility under tropical conditions-with special reference to season, temperature, and humidity (Vol. 2005). Wettemann, R. P., Wells, M. E., & Johnson, R. K. (1979). Reproductive Characteristics of Boars during and after Exposure to Increased Ambient Temperature. Journal of Animal Science, 49(6). 36