Source:JASE-W Japanese Smart Energy Products & Technologies

https://www.jase-w.eccj.or.jp/technologies/index.html

Keywords

Y2

Instrument

Z4

Electric power

S3

ZEB/BEMS
Azbil

Corporation

Actival™ motorized two-way valve with flow meter control function
Featuresu Realization of energy conservation
A continuously optimized flow rate is achieved by switching from a conventional
valve opening control to the flow rate control. An excessive flow rate is
restrained to reduce the number of heat sources and pumps in operation,
contributing to energy conservation. A circulating temperature compensation
control, which maintains the circulation temperature of the air conditioner coil at
a constant temperature and an application for reducing the transfer power of thepump, may be added for further energy conservation.
u Energy management
No additional equipment is required for energy management, since the valve isintegrated with temperature, pressure, flow rate and heat quantity
instrumentation functions. Energy management can be performed for eachindividual air conditioning unit, with space and cost savings.
u Improvement of comfort
The flow rate inside the air conditioning coil varies, as the pipe internal pressure
fluctuates, however, with conventional valve opening controls, in some cases,
the indoor temperature could not follow the set temperature. Controlling the flowrate, however, improves indoor comfort, as an optimum flow rate is sustained
the whole time, even when the pipe internal pressure fluctuates.
Overview or Principles
u Differences between controlsl Valve opening control(conventional control system)l Flow rate control (system adopted by ACTIVAL
with flow meter control function)
100%Control
output

100%Control
output0%0%Control output 0 to 100%R.A

Valve opening 0 to 100%

Indoor temperature
Indoor temperature setting

Featuring flow metercontrol function
ACTIVAL

O.A

FAN

R.A

Conventional valve

S.A

The output for the control valve opening isdetermined by the valve opening control, based on
the difference between the measured indoor
temperature (supplied air) and the set temperature.
Since the deviation of the measured indoor
temperature (supplied air), for the set temperature, isgreat when the air conditioning is turned on, or when
the temperature setting is excessively low, the control
valve opening becomes fully opened (100%) and, insome cases, the flow rate exceeds the design flowrate for the air conditioner coil (excessive flow).

Indoor temperature
Indoor temperature setting

O.AFANS.A

The flow control computes the flow rate setting byreferring to the deviation of the measured indoor
temperature (supplied air), for the set temperatureand controls the actuator to set the actual flow rate,according to the flow rate setting. An excessive flowrate is suppressed and the circulation temperature
difference of the secondary side cold-hot water canbe secured, since the flow rate setting will not exceed
the preset coil design flow rate (maximum flow rate)even if the difference between the measured indoor
temperature (supplied air) and the set temperature
becomes significant.

Effects or Remarks
Reference: Coil characteristic data

In the flow rate ranges above therated flow rate, the increase rateof the sensible heat exchange
quantity per flow rate below therated flow rate.

Excessive flow rate
range

Flow rate (l/min)Sensible heat
Coil outlet water temperature

Inlet air temperature 26°C
Inlet air humidity 50%RH
Supply water temperature 7°C
Return water temperature 12°C
Design flow rate 30l/min
Rated sensible heat quantity 50MJ/h

Temperature (°C)

u What is excessive flow rate?
An excessive flow rate refers to the phenomenon of a flow that exceeds
the design flow rate. This can occur depending on the pipe pressure
conditions, when the control valve opening is fully opened (100%), at thetime the air conditioning is turned on in the morning, or if the air
conditioning operation is set to an excessively low temperature. The
transfer power of the heat source pump is determined to ensure that therated flow for all air conditioning units, inside a building, is maintained.
Air conditioning units located on the highest floor of an office building,which is the furthest from the heat source unit, requires the most amountof transfer power. This can lead to an excessive flow rate at the airconditioning units installed on other floors and also, depending on thenumber of air conditioning units in operation, due to pressure variationsin the pipe system. Once an excessive flow rate occurs, the transfer
power of the heat source pump increases by that amount anddeteriorates from the heat source unit operating efficiency, which
ultimately leads to an increase in energy consumption.

Sensible heat (MJ/h)

F-88

Effects or Remarks

F-88

u The Control State of the Air Conditioner and the Effect of Reducing the Pump’s Transportation
Motive Power
A comparison study is made on the behaviour of the air conditioner during flow rate control and opening
control during the set up in the morning. From the comparison results, it shows a large deviation
between the actual air supply temperature and the air supply temperature set value. Fig. 1 shows thatwhen the opening control is conducted, the control valve’s opening is fully open and flows more than thedesigned flow rate, in another words, excessive flow rate, whereas the flow rate control is restricted toprevent exceeding the designed flow rate as seen from Fig. 2.
A further comparison between opening control, and flow rate control which is restricted to not exceed
the designed flow rate is also done during summertime and wintertime. The visual shows that it
contributes to a reduction in the pump’s transportation motive power as referred to Fig. 3.

Design flow rate
=80[l/min]

Supplied air temperatureSupplied airtemperature setting

Supplied airtemperature
setting

Actual flow rate

Transferpower
reducedby 12%

Transfer power (kwh)Design flow rate
=80[l/min]

Supplied air temperature

Actual flow rate

Valve opening
Flow rate
controlcontrol
SummerFigure 1: Air conditioning unit withvalve opening control (cooling)

Figure 2: Air conditioning unit withflow rate control (cooling)

Comparison of transfer power
between valve opening control
and flow rate control (for heating)Transfer power (kwh)Comparison of transfer power
between valve opening control
and flow rate control (for cooling)

Transferpower
reducedby 8%

Valve opening
Flow rate
controlcontrol
WinterFigure 3: Comparison of transfer power
between valve opening and flow rate controls<Actual data taken at our Fujisawa Technology Center>Note) A day’s worth of pump transportation motive power during both summertime and wintertime.
Comparison is conducted on days with almost equal treated calorific value.

Instantaneous flow rate x cold water temperature difference

Instantaneous flow rate x cold and hot water temperature difference

Temperature difference (°C)

Temperature difference (°C)

u Securing Supply and Return Temperature Difference
A different comparison is made on the supply and return temperature difference on the instantaneous
flow rate when using the existing valve and ACTIVAL™. When using the existing valve, as compared tothe 10ºC designed temperature difference, it cannot secure a temperature difference of 10ºC asgraphed in Fig. 5. On the other hand, when ACTIVAL™ is used, it secures a temperature difference of10ºC and above as displayed in Fig. 6.

Design temperature
difference ∆t = 10°C

Design temperature
difference ∆t = 10°C
cannot be securedDesign temperature
difference ∆t = 10°C

Flow rate (m3/h)

Design temperature
difference ∆t = 10°C
cannot be secured

Flow rate (m3/h)

Instantaneous flow rate x cold water temperature difference

Instantaneous flow rate x cold and hot water temperature difference

Temperature difference (°C)

Temperature difference (°C)

Figure 5: Circulation temperature difference with conventional valve(Left figure: Cold water; Right figure: Hot water)

Design temperature
difference ∆t = 10°C
Design temperature
difference ∆t = 10°C
can be secured

Flow rate (m3/h)

Design temperature difference∆t = 10°C can be secured

Design temperature
difference ∆t = 10°C

Flow rate (m3/h)

Figure 6: Circulation temperature difference withActival™ motorized two-way valve with flow meter control
Installation in Practice or Schedule
Domestic

Cumulative total of approximately 80,000 units sold

Overseas

Cumulative total of approximately 4,000 units soldContact:

Azbil Corporation
Building System Company, Global Sales Headquarters
TEL: +81-3-6205-7017
URL: https://www.azbil.com/