Siemens SITRANS 7ME3500, Operating Instructions Manual, Page: 123 / 296

Functions
7.8 Analog Input Setup
FUE1010 IP65 NEMA 4X
Operating Instructions, 12/2014, A5E03086491-AC
121
CE Method
The ultrasonic energy flow meters can be configured to provide an Energy Efficiency output.
Modifications were implemented using the standard analog input spanning methods in an
effort to simplify operator monitoring of air conditioning efficiency data. These changes allow
the flow meter to calculate chiller efficiency. The flow meter calculates chiller or heating
efficiency through use of an available analog input, which can be assigned to represent
power consumption (kW).
Note
Refer to www.EngineeringToolBox.com (
www.EngineeringToolBox.com ).
KW/ton
Cooling Load in kW/ton - Commonly used for large commercial and industrial air-
conditioning, heat pump and refrigeration systems. KW/ton is defined as the ratio of the rate
of energy consumption in kW to the rate of heat removal in tons at the rated condition. The
lower the kW/ton the more efficient the system.
kW/ton = P
c
/ E
r
where: P
c
= energy consumption (kW)
E
r
= heat removed (ton)
COP
Coefficient of Performance - COP is the basic unit less the parameter used to report the
efficiency of refrigerant based systems. COP is the ratio between useful energy acquired and
energy applied.
COP = E
u
/ E
a
Where: E
u
= useful energy acquired
E
a
= energy applied.
COP can be used to define both cooling efficiency or heating efficiency as with a heat pump.
● For cooling, COP is defined as the ratio of rate of heat removal to the rate of energy input
to the compressor.
● For heating, COP is defined as the ratio of the rate of heat delivered to the rate of energy
input to the compressor.
COP can be used to define the efficiency at a single standard or non-standard condition or a
weighted average seasonal condition. The term may or may not include the energy
consumption or auxiliary systems such as indoor or outdoor fans, chilled water pumps, or
cooling tower systems. For purposed of comparison the higher the COP the more efficient
the system.
COP can be treated as an efficiency where COP of 2.00 = 200% efficient. For unitary heat
pumps, ratings at two standard outdoor temperatures of 47°F and 17°F (8.3°C and -8.3°C)
are typically used.