Mixed-Humid Low-Load Monitoring - PHIUS · •Raleigh, NC •Engineering Research & Consulting Firm...
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Mixed-Humid Low-Load Monitoring David Treleven Advanced Energy
Transcript of Mixed-Humid Low-Load Monitoring - PHIUS · •Raleigh, NC •Engineering Research & Consulting Firm...
Mixed-Humid Low-Load Monitoring
David Treleven
Advanced Energy
Advanced Energy • Raleigh, NC
• Engineering Research & Consulting Firm
• Public Benefits Company Created by NC Utilities Commission
Original Intent of Study
• Test out mini-split heating, cooling & distribution systems
• Understand actual performance of low-load homes
Monitoring Set-Up
• Sub-meter (15 min interval)• Water Heater • Heat Pump• Solar• Main
• Temperature/RH• Heat Pump
• Return/Supply
• Master Bedroom• Crawl Space• HPWH Closets
Cooling Stages and RHHouses Being Monitored
Findings
1. High Dew Points
#2-
- #4 - #5 - #6
- #6 - #7 - #8
Average Dew Point @ Return
Month
House 5 6 7 8
4 60.7 59 58.6 57.7*
5 64.4 60.8* - -
6 58 64.5 60.6* -
7 59.8 58.2 60.4 61.2
8 59.9 59.2 58.1 56.9
9 59 58.6 60.8 59.6
Passive Houses Have More Internal Moisture
2. Coils Not Maintaining Dew Point
Ductless MSHP – Greensboro - June
Khattar, M K, M V Swami, and N Ramanan, "Another Aspect of Duty Cycling: Effects on Indoor Humidity." FSEC-PF-118-87, Florida Solar Energy Center, Cape Canaveral, FL 32920. ASHRAE Transactions, January 1987.
-15
-10
-5
0
5
10
15
20
25
40
45
50
55
60
65
70
75
12
:00
AM
4:1
5 A
M
8:3
0 A
M
12
:45
PM
5:0
0 P
M
9:1
5 P
M
1:3
0 A
M
5:4
5 A
M
10
:00
AM
2:1
5 P
M
6:3
0 P
M
10
:45
PM
3:0
0 A
M
7:1
5 A
M
11
:30
AM
3:4
5 P
M
8:0
0 P
M
12
:15
AM
4:3
0 A
M
8:4
5 A
M
1:0
0 P
M
5:1
5 P
M
9:3
0 P
M
1:4
5 A
M
6:0
0 A
M
10
:15
AM
2:3
0 P
M
6:4
5 P
M
11
:00
PM
3:1
5 A
M
7:3
0 A
M
11
:45
AM
4:0
0 P
M
8:1
5 P
M
12
:30
AM
4:4
5 A
M
9:0
0 A
M
1:1
5 P
M
5:3
0 P
M
9:4
5 P
M
2:0
0 A
M
6:1
5 A
M
10
:30
AM
2:4
5 P
M
Ret
urn
-Su
pp
ly G
rain
s o
f m
ois
ture
Sup
ply
Tem
p (
F)
Time
Ducted MSHP - August
Temp, °F Return - Supply Grains of Moisture
Ducted MSHP Cooling Season
Dry Mode
3. Design/Behavior Issues
Mechanical Plans
4. Detailed Ductless Performance
Monitored Capacity
Total Cooling
Latent
Monitored Capacity
SHR 1.52*
SHR 1.52*
SHR = Sensible/Total
Sensible Cooling Only(10000Btu/hr )/(10000Btu/hr)= 1.0
Cooling with Dehumidification(7000Btu/hr )/(10000Btu/hr)= 0.7
Cooling with Humidification
(10000Btu/hr )/(7000Btu/hr)= 1.43
Monitored Capacity
SHR 0.65*
Review
• High interior moisture
• Mini-split coils not maintaining dew point/re-humidification
• Design/behavioral issues affecting comfort
• Potential to optimized mini-splits for additional moisture removal
