Pig Housing Systems Designed to

Manage or Adapt to Climate Change

Presented at:

Minnkota Meeting

March 16, 2012

Larry D Jacobson, Professor & Extension Engineer

University of Minnesota

Introduction

• Generally accepted that climates in the

major pig production areas of the U.S.

(Midwest and Southeast) are becoming

warmer with higher moisture or dewpoint

temperatures.

• A warmer and wetter climate will only

increase the need to lower barn

temperatures in production facilities, which

is very limited in present building designs.

“Green Pig Barn” Project Objectives

• Develop a swine finishing building for

Midwestern U.S. based on building design

criteria that reduces the housing system’s

environmental footprint (lowers energy & water

usage and airborne emissions by 50%) while

maximizing utilization of manure/waste

products

• Provide guidance to retrofit existing finishing

barns to reduce energy use and emissions.

Key Design Criteria

• Integrated Design

– No add on technologies that do not benefit the

production system

• Replace current 2400 head “tunnel ventilated”

finishing barn in upper midwest (traditional deep

pit with curtain or power ventilation)

• Must account for total housing system

emissions (e.g. manure storage emissions

must be included)

Tunnel Ventilated Finishing Barn

• Double wide- 2 – 1200 rooms

or 2400 head total – approx.

max ventilation 120 cfm/pig

• Winter ventilation – mostly

pit fans but some end wall

fans using ceiling inlets

• Summer ventilation – both

pit and all end wall fans with

primary inlets from opposite

end wall curtain

Other Important Factors

• Design should optimize the barn

environment AND pig performance to offset

added capital investment or labor costs Thermoneutral Zone

Heat Production in Growing Pigs

0

200

400

600

800

1,000

22 44 66 88 110 132 154 176 198 220

Pig Wt, lb

BT

U/h

r

Today Pre-1988

Trans ASAE 47(1):259-270

111% 115%

Other Factors to Consider

• Design should improve worker environment

and reduce safety hazards (foaming and H2S

hazards with agitation and pumping)

Other Important Factors

• Emissions, energy, and economics

calculated on per pound of pork produced

rather than on per area or animal number

– Emissions may be more per barn but if more

product (pork) is produced . . . we are getting

less emissions per unit of production

Energy Use in Pig Production

• Direct (Fossil Fuel) Energy

– Primarily L.P. Gas and electricity

– About 2 to 5% of pig production cost (UMN

Farm Financial Management)

• Indirect (Feed) Energy

– Feed efficiency, rate of gain

– Estimated to be 60 to 70 %

of pig production costs

Key Emission Control Factors

• Move manure out of the barn – avoid long-

term pit storage of manure under barn

– Reduces risks of pig losses during pumping

– Improves Indoor Air Quality

– Reduce ventilation requirements

– Reduce barn emissions

• Reduce ventilation

• Reduce temperature

Mean Ventilation Rates over 12 months for

Geothermal vs. Conventional Crated Gestation

Final Design Summary

• 2400 head, double wide, mechanically

ventilated barn

• Ceiling inlets for 100% of ventilation air

• Four barn versions (A,B,C,&D)

– Flooring (partial slats - A & B & full slats –C & D)

– Different Heating and cooling systems

Barn Design Options Matrix Partially Slatted Version A: Geothermal

and heat pump for

heating and cooling (PEX

tubing) floor (40 T

heating and cooling) plus

direct fire for room heat.

(80 cfm/pig max)

Version B:

Geothermal only

heating and cooling of

floor and room (135 T

heating and cooling)

(40 cfm/pig max)

Fully Slatted Version C: Evaporative

Cooling only (twice

normal cooling capacity)

(100 cfm/pig)

Version D:

Geothermal heating

and cooling of room

air (135 T heating and

cooling) (40 cfm/pig

max)

NOTE: All barns include outdoor covered manure storage

Versions A and B

Versions C and D

Green grow-finish barn’s

inlets & air tempering

• Tempering halls at ends of barns for heat

exchangers or cool cells

• All air brought in through ceiling inlets

Energy and Emissions Estimates (in comparison with existing tunnel ventilated barns)

Version of

Barn

Electric use LP use Emissions

Version A Slightly more Slightly less less

Version B Slightly less Slightly less Much less

Version C Equal Equal Slightly less

Version D Slightly less Slightly less less

Economic Evaluation1

Variables Considered

• Investment

• Feed efficiency

• Death loss

• Pig health cost

• Electric use

• LP use

• Market Price

• Other costs

Constants

• Start and end weight

• Weaned pig cost

• Days to end group

• Between Group Time

• Feed cost

• Facility life

1Done by Bill Lazarus and Bob Koehler

Key Input parameters that were

varied for the Economic Analysis

Item Baseline Version A Version B Version C Version D

Const. costs /

pig space1

$260 $400 $510 $350 $525

ADG2

lb/day

1.55 1.62 1.66 1.60 1.66

FE2

lb feed/lb gain

2.75 2.55 2.45 2.60 2.45

1Bids from SW MN field engineers to build barn & manure storage 2,3Based on 2009 Finbin records of 36 farms with adjustments for cooled facilities

Economic Summary - Results

Item Baseline Version A Version B Version C Version D

Profit/pig $3.73 $6.65 $4.95 $8.18 $5.30

NPV1/pig

space

$5.95 $2.43 $9.03 $3.12

Years to

Payback

additional to

baseline

1Net Present Value

9.1 12.8 6.0 12.5

Economic Analysis Discussion

• Many assumptions & crude sensitivity analysis

– Slight changes in animal performance (ADG

and FE) will have dramatic impact on results

– Feed costs will also have a large impact

• Not captured by Economic Analysis

– Worker health, regulations and permitting

benefits, death loss (pigs) with agitation and

pumping

Questions??

Heat

Percent of air exhausted to remove CO2

Makeup air added to replenish O2

Pigs

Add Heat, Moisture, and Gasses to Air

Optional Antimicrobial

Filter in makeup air

Bacteria, Viruses, and Dust Removal

Water to Air Heat Exchanger

Heat Added

Combination of Biotrickling and Biofilter

H2S, NH3, and other Gasses Removal

Water to Air Heat Exchanger

Heat Removed for

Dehumidification

Moisture removed from air

Water

Heat Storage

Heat A

B

C D

E

F

G

24

• Develop a new barn design concept for

swine production that would reduce

emissions and improve feed efficiency.

25

AirCleaner

&Conditioner

26

AirCleaner

&Conditioner

Air Cleaner and Conditioner Units

27

28

Biotrickling Filter

Biofilter

Air Inlet

CO2 Exhaust Fan

Heat/Water Storage Tank

Air Return to Swine Room

Heat Exchanger to cool air and Condense Moisture

Heat Exchanger to Reheat Air

Ambient Air InletHeat Pump

29

60'

30'

100'

260'

InstrumentRoom

Show

er Conference &

Break roomBathroom

Baged Feed Storage Area

MechanicalRoom

Tunnel Ventilation

Mechanically VentilationRecirculating Air Ventilation

Office

Observation Hallway