1. Environmental Systems and Facilities Planning
Doug Overhults
University of Kentucky
Biosystems & Agricultural Engineering
University of Kentucky
College of Agriculture

2. Topic Outline Psychrometrics Review Energy Balances/Loads
Latent heat
Sensible heat
Solar loads
Insulation Requirements

3. Topic Outline Ventilation Systems Moisture Control Standards
Rate requirements
System requirements
Moisture Control Standards
Air Quality Standards
Humans
Animals
Plants and Produce

4. Psychrometrics Variables Using the Psychrometric Chart
Psychrometric Processes

5. Psychrometric Chart “Humidity” Scale or axis
State Point
Dry Bulb Temperature Scale (axis)

6. Psychrometric Chart (temperatures + relative humidity)
Example:
70 oF dry bulb
55 oF dew-point
61 oF wet-bulb
60 % rh
relative humidity
“Humidity” Scale
dew-point
wet bulb
dry bulb
Dry Bulb Temperature Scale

7. Psychrometric Processes
Heating, cooling, humidifying, dehumidifying air-water vapor mixtures
Five basic processes to know
Heat or Cool (horizontal line)
Humidify or De-humidify (vertical line)
Evaporative cooling (constant wet-bulb line)

8. Heating: dry bulb increase
“Humidity” Scale
Horizontal line means no change in dew-point or humidity ratio
ending state point
starting state point
Dry Bulb Temperature Scale

9. Humidification: dew-point increase
“Humidity” Scale
Vertical line means no change in dry bulb temperature
RH goes up!
end state
start state
Dry Bulb Temperature Scale

10. Evaporation: wet bulb increase
“Humidity” Scale
Increase in vertical scale: humidified
Decrease in horizontal scale: cooled
end state
Constant wet bulb line
start state
Dry Bulb Temperature Scale
Adiabatic process – no heat gained or lost (evaporative cooling)

11. Air Density “Humidity” Scale Dry Bulb Temperature Scale Wet bulb line
Humid Volume, 1/
ft3/lb da
Dry Bulb Temperature Scale

12. Review Name three temperature variables
Name three measures of humidity
Name the two main axes of the psychrometric chart
Name the line between fog and moist air
Heating or Cooling follow constant line of ?
Humidify/Dehumidify follow constant line of ?

13. Energy and Mass Balances

14. Energy and Mass Balances
Heat Gain and Loss
Latent and Sensible Heat Production
Mechanical Energy Loads
Solar Load
Moisture Balance

15. Heat Gain and Loss Occupants Lighting Equipment Ventilation
Building Envelope
Roof, walls, floor, windows
Infiltration (consider under ventilation)

16. Heat Loads Occupant (animals, people) Lighting, W/m2 Appliance W/m2
Sensible load (e.g. Btuh/person)
Latent load (“)
Lighting, W/m2
Appliance W/m2
Ventilation air (cfm/person or animal)
Equipment (e.g. Btuh for given items)

17. Ventilation Temperature control Moisture control
Contaminants (CO2, dust, NH3) control
Energy use

18. Latent and Sensible Heat Production
Example from ASAE Standard EP270.5:
Table 1. Moisture Production, Sensible Heat Loss,
and Total Heat Loss
Cattle Bldg. T MP SHL THL
500 kg C gH2O/kg-h W/kg W/kg

19. Sensible Energy Balance
Leads to Ventilation for Temperature Control:
qs + qso + qm + qh = ΣUA(ti-to) + FP(ti-to) + cpρV (ti-to)
Heat inputs = envelope + floor + ventilation
U – building heat transfer coeff.
P – floor perimeter
F – perimeter heat loss factor
cp – specific heat of air
V – ventilation rate
ρ – density of air
qs – sensible heat
qso – solar heat gain
qm – mechanical heat sources
qh – supplemental heat

20. Sensible Energy Balance
Leads to Ventilation for Temperature Control. Rearranging:
V = [ qs - ( Σ UA+ FP)(ti-to)] / 0.24 ρ (ti-to)60
V – cfm (equation for English units)

21. Mass Balance
Moisture, CO2, and other materials use balance equations. mp
Material produced
mvi
Material input rate
mvo
material output rate + =

22. Humidity ratio difference
Moisture Balance
Example balance for moisture control removal rate. /
mair
Ventilation rate
Mwater
Moisture to be removed
(Wi-Wo)
Humidity ratio difference =
Q = (V / 60) x [ Wr / (Wi-Wo) ]
Q - cfm V – ft3/lbda Wr – lbm / hr W – lbm / lbda

23. Moisture Balance Find the minimum winter ventilation rate to maintain
60% relative humidity inside a swine nursery that has
a capacity of 800 pigs weighing 10 pounds. Inside
temperature is 85 degrees.
ASABE D270.5
Nursery
Pigs Bldg. T MP SHL THL
4 - 6 kg C gH2O/kg-h W/kg W/kg

24. Find the minimum winter ventilation rate to maintain
60% relative humidity inside a swine nursery that has
a capacity of 800 pigs weighing 10 pounds. Inside
temperature is 85 degrees.
Find moisture production data
ASABE Standards (EP270.5)
Wr = lb/hr/pig
Get psychrometric data from chart
W0 =
Wi =
V = 14.1
Plug into equation & solve
Q = (14.1/60) x [(.017 x 800) / ( )]
Q = 214 cfm

25. NH3 Balance Find the ventilation rate required to prevent the
ammonia concentration inside a poultry layer barn
from rising above 20 ppm. Ammonia production
in the barn is estimated to be 21.6 cubic feet
per hour. Ammonia concentration in the
ambient air is 2 ppm.

26. NH3 Solution Use volumetric form of mass balance equation Vp + Vi = Vo
Vp + Qv[NH3]i = Qv[NH3]o
Solve for Qv
Qv = Vp / { [NH3]o - [NH3]i }
Get quantities in consistent units
Vp = (21.6 ft3/hr / 60 min/hr) = 0.36 ft3/min
Plug into equation & solve
Q = 0.36 / ( )]
Q = 0.36 /
Q = 20,000 cfm

27. Energy Balance
What is the ventilation rate for a swine finishing barn that will limit the design temperature rise inside the house to 4 degrees (F) above the ambient temperature? The barn capacity is 1000 pigs at 220 pounds and the inside temperature is approximately 85 F. The overall heat transfer coefficient for the barn is 1200 Btu/hr F.

28. Find heat production data ASABE Standards (EP270.5)
What is the ventilation rate for a swine finishing barn that will limit the design temperature rise inside the house to 4 degrees (F) above the ambient temperature? The barn capacity is 1000 pigs at 220 pounds and the inside temperature is approximately 85 F. The overall heat transfer coefficient is 1200 Btu/hr F.
Find heat production data
ASABE Standards (EP270.5)
q = 0.49 W/kg (sensible heat)
Convert units & calculate total heat load
q = 0.49 W/kg x 100 kg/pig x 1000 pigs
= 49,000 W x Btu/hr W
= 167,188 Btu/hr
Density of Air = lb/ft3
Specific heat of air = 0.24 Btu/lb F
ti – to = 4 F

29. Neglect floor heat loss or gain Plug into equation & solve
Continuation ventilation rate for a swine finishing barn that will limit the design temperature rise inside the house to 4 degrees (F) above the ambient temperature
Basic equation
Neglect floor heat loss or gain
Plug into equation & solve
V = [167,188 - (1200 x 4)] / [(0.24 x 0.075) x 4 x 60]
V = 37,590 cfm
V = [ qs - ( Σ UA+ FP)(ti-to)] / 0.24 ρ (ti-to)60

30. Ventilation volumetric flow rate
Fan Operating Cost
Electrical Power Cost V
Ventilation volumetric flow rate W
Power input, Watts
cfm / Watt
Fan Test Efficiency = ÷

31. Calculate Operating Costs
Design Ventilation Rate – 169,700 cfm
Fan Choices
Brand A – 21, cfm/watt
Brand B – 22, cfm/watt
Fans operate 4000 hours per year
Electricity cost - $0.10 per kWh
Calculate annual operating cost difference

32. Calculate Operating Costs
8 fans required for brand A or B
Use EP 566, Section 6.2
Annual cost is for all 8 fans
Watts * hrs * $/kWh * kWh/Wh = $

33. References – Env. Systems
Albright, L.D Environment Control for Animals and Plants. ASAE
Hellickson, M.A. and J.N. Walker Ventilation of Agricultural Structures. ASAE
ASHRAE Handbook of Fundamentals

34. Reference MWPS - 32 Midwest Plan Service Iowa State University
Contains ASABE heat & moisture
production data & example problems
Midwest Plan Service
Iowa State University
Ames, IA

35. Reference STRUCTURES and ENVIRONMENT HANDBOOK MWPS - 1
Broad reference to cover agricultural
facilities, structures, & environmental control
Midwest Plan Service
Iowa State University
Ames, IA

36. Useful References – Env Sys
MidWest Plan Service MWPS-32, Mechanical Ventilation Systems for Livestock Housing.
Greenhouse Engineering (NRAES – 33) ISBN http://palspublishing.cals.cornell.edu/nra_order.taf

37. References – ASAE Standards
EP270.5 – Ventilation systems for poultry and livestock
EP282.2 – Emergency ventilation and care of animals
EP406.4 – Heating, ventilating cooling greenhouses
EP460 – Commercial Greenhouse Design and Layout
EP475.1 – Storages for bulk, fall-crop, irish potatoes
EP566 – Selection of energy efficient ventilation fans

38. FACILITIES Manure Management Example

39. Manure Management Facilities
Animal Manure Production
Nutrient Production
Design Storage Volumes
Lagoon – Minimum Design Volume
References
ASAE – EP 384.2, 393.3, 403.3, 470
NRCS – Ag. Waste Field Handbook

40. Size a Manure Storage 1 year storage
Above ground 90’ dia. tank – uncovered
2500 hd capacity – grow/finish pigs
Building turns over 2.7 times/yr
Manure production 20 ft3/finished animal
Net annual rainfall = 14 inches
25 yr. – 24 hr storm = 5.8 inches

41. Size a Manure Storage Use EP 393, sections 5.1 & 5.3
Total volume has 5 components
Manure, Net rainfall, 25 yr-24 hr storm
Incomplete removal, Freeboard for agitation

42. Size a Manure Storage Manure Depth = 21.22 ft. Net rain = 1.17 ft
25 yr-24 hr storm = 0.48 ft
Incomplete removal = 0.67 ft
Freeboard = 1 ft
Total Tank Depth = ft.

43. References - Facilties
Agricultural Wiring Handbook,  15th edition, Rural Electricity Resource Council
Farm Buildings Wiring Handbook, MWPS-28 (now updated to 2005 code)
Equipotential Plane in Livestock Containment Areas ASAE, EP473.2
Designing Facilities for Pesticide and Fertilizer Containment, MWPS-37
On-Farm Agrichemical Handling Facilities, NRAES-78
Farm and Home Concrete Handbook, MWPS-35
Farmstead Planning Handbook, MWPS-2
(download only)

44. References – ASAE Standards
D384.2 – Manure Production and Characteristics
EP393.3 – Manure Storages
EP403.4 – Design of Anaerobic Lagoons for Animal Waste Management
EP470.1 – Manure Storage Safety
S607 – Ventilating Manure Storages to Reduce Entry Risks

45. Thank You and Best Wishes for Success on Your PE Exam ! !
University of Kentucky
College of Agriculture
Biosystems & Agricultural Engineering