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Thermostatic balancing valvesin hot water circulation systems
W.G. van der Schee (TVVL)W.J.H. Scheffer (TVVL)
May 2018 IAPMO_20182
IntroductionW.G. (Walter) van der Schee
Croonwolter&dros, NetherlandsContractor for MEP installations in commercial buildings.
Works in the field of mechanical and plumbing installations.
Presentation on behalf of the TVVL.Association for engineers in the field of building services.Member of the TVVL Expert group Sanitary Installations.
Thermostatic balancing valvesin hot water circulation systems
IAPMO_2018
Contents1. Backgrounds2. Calculations3. Thermostatic balancing valves in practice4. Conclusions and discussion
May 20183
1. Backgrounds
May 20184 IAPMO_2018
Hot drinking water system in hotels, hospitals etc.
Static balancingvalves
Temperaturesaccording Dutchstandard
65 °C / 149 °F
≥60 °C / 140 °F
± 62 °C / 144 °F
1. Backgrounds
May 20185 IAPMO_2018
Thermostaticbalancing valves
65 °C / 149 °F
≥60 °C / 140 °F
± 62 °C / 144 °F
Hot drinking water system in hotels, hospitals etc.
1. Backgrounds
May 2018 IAPMO_20186
Source: Kemper, Hochschule Münster
Flow rates thermostatically regulated circulation systemTop curveTemperature begincirculation loop
Pink curveTemperature endcirculation loop
1. Backgrounds
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Experiences in practice:
• 60 °C at inlet hot water producer is not reached
• 62 °C at the end of the circulation loops is not reached
• High heat loss
• Bad quality thermal insulation
1. Backgrounds
May 2018 IAPMO_20188
Questions:• Appropriate calculation available?• Is the circulation system balanced?• Lack of knowledge?• Gap between theoretical approach and practice?• Other causes?
These questions made us decide to do an investigation.
How can we improve the performance of the TBV in HWS?
2. Calculations
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b
ql
ga
r
2. Calculations
May 2018 IAPMO_201810
a = 65 °C
r = 60 °C
b = 64.73 °C
q = 60.38 °C
Heat loss 475 W0.026 l/s
The heat loss depends on:• Pipe size• Length• Thermal insulation
ΔT:• Supply a – b = 0.27 K• Circulation q – r = 0.38 K• Loop b ‐q
May 2018 IAPMO_201811
2. Calculations
65 °C
60 °C
63.23
61.24
∆T supply 1.8 K → 0.22 K / 8 m∆T circulation 1.2 K → 0.15 K / 8 m
l = 60.87 °C
3. Thermostatic balancing valves in practice
May 2018 IAPMO_201812
Several manufacturers on the market.A random selection for the purpose of TVVL investigation.
Multi-Thermfig. 141 OG Thermostatic
AquastromT-plusThermostatic
NO disapproval ofthe products or suppliers!
3. Thermostatic balancing valves in practice
May 2018 IAPMO_201813
Kemper• Accuracy ± 2 K• Adjustable range 50 – 65 °C• Factory pre‐set 58 °C (German value)
o Be aware of the required set‐point!• Sizes DN 15 (½”) , 20 (¾”)and 25 (1”)
May 2018 IAPMO_201814
3. Thermostatic balancing valves in practice
Rotaryshut‐off cap
Locking‐screw
Hex key
Adjusting cap
Plug
Balancing head
Step 59 – 61 °C
Challenge to adjust on 60.87 °C!
Marker arrow
May 2018 IAPMO_201815
3. Thermostatic balancing valves in practice
Example loop g - l
l = 60.87 → 61 °CAccuracy ± 2 K
CalculatedKv-value 0.51 m3/h
70 °C61
0.51
52
Factory set‐point
58 62
Calculated set‐point
≤ 52 °CKv-value → 1.3 m3/h
1.30
May 2018 IAPMO_201816
3. Thermostatic balancing valves in practiceMeasuring temperatures in a hotelTT09
TT01 TT02
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3. Thermostatic balancing valves in practice72
67
6266
56
46
61
51
4164
59
54
49
Outlet hot water
Loop 01
Loop 02
11:00 13:00 15:00 17:00 19:00 21:00 23:00 00:00 02:00 05:00 07:00 09:00 11:00
Oventrop Aquastrom T‐plus.
Result:• Changes in larger diameters
o Higher heat losso Higher flow rateso Larger balancing valves
• Calculation according German standardo Velocity 0.7 instead of 1.5 m/s → larger pipe sizeso Dutch technician isn’t aware about thiso He expects reliable calculations
May 2018 IAPMO_201818
3. Thermostatic balancing valves in practice
AquastromT-plusThermostatic
4. Conclusions and discussion
Conclusions:• Start with an accurate calculation.• Use thermal insulation, thickness 35 mm.• Check and adjust set‐point temperature.• TBV requires a proper design (Static BV as well).• TBV can’t substitute a bad design.• TBV can’t substitute a badly constructed HWS.
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4. Conclusions and discussion
Conclusions:• The manufacturers:
o Offer to make calculationso Use their own softwareo The results differ from the basic assumptionso They can’t provide Kv‐values
• Technicians aren’t aware about it• Around the performance of TBV question marks still exist.
What experiences do you have with TBV?
IAPMO_2018May 201820
Thermostatic balancing valvesin hot water circulation systems
W.G. van der ScheeW.J.H. Scheffer
Personal biographyWalter van der Schee BSc is an employee of Croonwolter&dros based in Amersfoort the Netherlands. He is responsible for mechanical and plumbing design and construction in commercial buildings.
As member of the Dutch Technical Association for Building Installations (TVVL). He is one of the experts consulting for Plumbing technologies. For his work within the TVVL he was awarded the BJ Max award in 2006.
For further information about Walter’s employer or the TVVL association consult their websites. www.croonwolterendros.nlwww.tvvl.nl
E‐mail: [email protected]
May 2018 IAPMO_201822
