HEATING AND COOLING MEASUREMENT
The Energy model is designed to measure the rate and quantity of heat delivered to a given building, area or heat exchanger.
The instrument measures the volumetric flow rate of the heat exchanger liquid (water, water/glycol mixture, brine, etc.), the
temperature at the inlet pipe and the temperature at the outlet pipe. Heat delivery is calculated by the following equation:
Rate of Heat Delivery
QKdV
V
V
=
∫
∆
θ
0
1
Platinum RTD
Type 1000 Ohm
Accuracy ±0.3 °C (0.0385 curve)
Temperature Response Positive Temperature Coefficient
Where:
Q = Quantity of heat absorbed
V = Volume of liquid passed
K = Heat coefficient of the liquid
θ = Temperature difference between supply
and return
The RTD temperature measurement circuit in the Energy model measures the differential temperature of two 1000 Ohm,
three-wire platinum RTDs. The three-wire configuration allows the temperature sensors to be located several hundred feet
away from the transmitter without influencing system accuracy or stability.
The Energy model allows integration of two 1000 Ohm platinum RTDs with the energy transmitter, effectively providing
an instrument for measuring energy delivered in liquid cooling and heating systems. If RTDs were ordered with the energy
transmitter, they have been factory calibrated and are shipped connected to the module as they were calibrated.
Field replacement of RTDs is possible thru the use of the keypad or the UltraLink software utility. If the RTDs were ordered
from the manufacturer of the Energy model, they will come with calibration values that need to be loaded into the
Energy model.
New, non-calibrated RTDs will need to be field-calibrated using an ice bath and boiling water to derive calibration values. This
procedure is outlined below.
Heating and Cooling Measurement
Page 91 May 2016 TTM-UM-00136-EN-06
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