Designing Residential Ventilation for Indoor Air Quality ...
Precision ventilation to improve indoor air quality … · Precision ventilation to improve indoor...
Transcript of Precision ventilation to improve indoor air quality … · Precision ventilation to improve indoor...
Department of Engineering
Aarhus University
Guoqiang Zhang 1
Precision ventilation to improve indoor air
quality and reduce emission in pig housing
Guoqiang Zhang Dept. of Engineering, Aarhus University, Denmark.
E-mail: [email protected]
- Danish experiences of pit air exhaust
Department of Engineering
Aarhus University
Guoqiang Zhang
Partial Pit Air Exhaust (PPAE)
- Concept
- In a mechanical ventilation system
- In a natural ventilation system
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Using an extra air exhaust to remove the
part of most pollutant air directly from
slurry pit headspace.
Department of Engineering
Aarhus University
Guoqiang Zhang 3
Systems with mechanical
ventilation
- Ceiling diffusion/jet inlet
- Side-wall jet inlet
Department of Engineering
Aarhus University
Guoqiang Zhang
With ceiling diffusion inlet – Fully slatted
floor
0-90%
5-10%
4 Pit air supply
Department of Engineering
Aarhus University
Guoqiang Zhang
With Ceiling diffusion inlet & Ceiling jet inlet
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Department of Engineering
Aarhus University
Guoqiang Zhang
With Sidewall jet inlet
0-90%
5-10%
6 Pit air supply
Department of Engineering
Aarhus University
Guoqiang Zhang
Pit ventilation layout under the slatted floor - An example
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Slu
rry p
it
Pit ventilation duct
Air supply tube with inlet
holes downward 45 °
Department of Engineering
Aarhus University
Guoqiang Zhang
In systems with ceiling diffusion inlet
– Fully production scale
A graphic by Danish Pig research, 2013
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Ceiling top exhaust
(main exhaust)
Pit exhaust
Department of Engineering
Aarhus University
Guoqiang Zhang
In systems with ceiling diffusion inlet
– Fully production scale
A photo by Danish Pig research, 2014
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Pit exhaust
air duct
Ceiling top exhaust
Department of Engineering
Aarhus University
Guoqiang Zhang
In systems with natural
ventilation
• Enhance indoor climate control – focus
on airflow pattern/air distribution
• Reduction of environmental impacts
due to dust/gas emission and
improving indoor air quality – with
effective air purification units at pit
exhaust
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Department of Engineering
Aarhus University
Guoqiang Zhang
In a naturally ventilated livestock building
In winter, it may increase
wall inlet jet momentum by
closing ridge top opening &
using only PPEV.
In most of operation period
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Department of Engineering
Aarhus University
Guoqiang Zhang
In a naturally ventilated cattle building:
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Department of Engineering
Aarhus University
Guoqiang Zhang
Summary of NH3 emissions from Danish fattening pig
facilitiesa with conventional or PPAE ventilation systems
Source Ventilation
system
Via exhaust Ventilation rate,
m3 h-1 pig-1
NH3 concentration,
ppm
NH3 emission,
g d-1 pig-1
% of emission via pit
exhaust
Koerkamp
et al. (1998) Conventional Ceiling exhaust - 14.9 7.7 -
Saha et al.
(2010) b Conventional Ceiling exhaust 48.7 6.5 4.1 -
Ceiling exhaust 61.4 3.8 2.5
PPAE Pit exhaust 11.6 10.8 1.9 43.2%
Total 80.0 - 4.4
Pedersen &
Jensen
(2010)
Conventional Ceiling exhaust 52 9.3 7.5
Ceiling exhaust 49 2.6 1.8
PPAE Pit exhaust 10 20 3.3 64.7%
Total 59 - 5.1
Zhang et al.
(2014) Ceiling exhaust 75.5 1.8 2.4
PPAE-F1 c Pit exhaust 13.3 12.5 3.0 55.6%
Total 88.8 - 5.4
Ceiling exhaust 80.6 2.3 3.0
PPAE-F2 d Pit exhaust 12.0 18.6 3.8 55.1%
Total 92.6 - 6.9
Zong et al.
(2014) c Ceiling exhaust 83.4 2.1 2.9
PPAE-C e Pit exhaust 9.9 16.6 2.7 48.2%
Total 93.3 - 5.6
Ceiling exhaust 68.1 3.4 3.8
PPAE-W f Pit exhaust 9.3 21.3 3.3 46.5%
Total 77.4 - 7.1 a all with fully or partial slatted floor; b measurement at early and middle of the fattening period; c F1 with 67% slatted floor & 33% drain floor; d F2 with part of slatted floor (1 × 2 m2) was covered; e C with diffusion ceiling / ceiling jet air inlet; f W with side-wall jet air inlet. 13
Department of Engineering
Aarhus University
Guoqiang Zhang
Ammonia emission, example Toal ammonia emission & removed via pit exhaust
y = 0.1003x - 1.1157
R2 = 0.9223
0
2
4
6
8
10
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0 15 30 45 60 75 90 105
Pig Weight, kg pig-1
NH
3 e
mis
sio
n, g
d-1
pig
-1
○, total emission; Δ, ammonia removed via pit exhaust
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Department of Engineering
Aarhus University
Guoqiang Zhang
Important parameters for PPAE
• Ventilation rate for PPAE
• Room airflow patterns
• Floor opening ratio & configuration
• Animal’s lying area/location – buoyant force & floor covering
• PPAE opening locations
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Department of Engineering
Aarhus University
Guoqiang Zhang
Simulation of flow in building
Air flow pattern and velocity distribution (m/s) in symmetry plane of the pen at
outdoor temperature of 20 °C and no pit exhaust. To the left: Diffuse ceiling air
inlet. To the right: Diffuse ceiling in combination with ceiling air jet inlet.
Air flow pattern and velocity distribution (m/s) in symmetry plane of the pen at
outdoor temperature of 10 °C and no pit exhaust. To the left: Diffuse ceiling air
inlet. To the right: Wall jet inlet.
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Department of Engineering
Aarhus University
Guoqiang Zhang
References: - Bjerg, B., Zhang, G., & Kai, P. (2008). CFD Investigation of a Partly Pit Ventilation
System as Method to Reduces Ammonia Emission from Pig Production Units. In
Proceedings of the Eighth International Livestock Symposium (ILES VIII), Paper No.
0169, Iguassu Falls, Brazil, August 31-September 4, 2008
- Riis, A.F., Jørgensen, M., Hansen, P., 2014a. 10 % Punktudsugning via sugepunkt
midt under lejeareal i slagtesvinestald med drænet gulv i lejearealet (10 % Point air
exhaust with the exhaust opening under drain floor of the laying area in fattening pig
house, in Danish). Meddelelse 998, Videncenter for Svineproduktion (Danish Pig
Research)
- Rong L; Liu D; Pedersen E; Zhang G. (2014). Effect of climate parameters on air
exchange rate and ammonia and methane emissions from a hybrid ventilated dairy
cow building. Energy and Buildings, 82: 632–643
- Saha C K; Zhang G; Kai P; Bjerg B (2010). Effects of a Partial Pit Ventilation System
on Indoor Air Quality and Gaseous Emissions from a Growing/Finishing Pig Building.
Biosystems Engineering, 105(3), 279-287
- Zong C; Feng Y; Zhang G; Hansen MJ. (2014). Effects of different air inlets on indoor
air quality and ammonia emission from two experimental fattening pig rooms with
partial pit ventilation system - summer condition. Biosystems Engineering, 122: 163-
173
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