Thermo Products USDT 2004B - Manual (Page 14)

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nergy calculation - Energy gain is calculated by obtaining the temperature increase of
the heat transfer fluid as it crosses the solar collector. The amount of fluid flow through
the collector is registered by an in-line flow meter. USDT 2004 computes the energy production
as a function of the temperature differential and fluid volume. In addition, the system anti-freeze
(Glycol) percentage should be entered as it affects the thermal conductivity and heat transfer
rate.
BTU
Energy calculation mode
S IN Sensor port selection for inlet temperature (1, 2, 3, --)
S OUT outlet temperature (1, 2, 3, --)
F SEN Sensor port selection for flow rate (1, 2, 3, --)
Energy calculation will be initiated only after temperature sensor ports are designated. Flow rate
can be either a constant number to be entered by user, or from a flow meter input. To activate the
energy calculation without using the flow meter's impulse input, a dash (-) must be selected for F
SEN channel followed by the constant flow rate in gph (gallon per hour) unit:
GAL
Constant flow rate in gph instead of flow meter reading in (--) sensor mode
Select 3 for F SEN when a flow meter is used:
LPP
Flow meter rate impulse number in liter per pulse, if flow meter is used
GLYCOL Anti-freeze percentage
DIF (- Sensor calibration
The output of USDT 2004 unit is kW for system power and kWh or MWh for collected energy. The
energy calculation dependents on flow meter accuracy, the temperature sensors class, and their
locations. The flow meter is a mechanical device and its accuracy fluctuates over time. Therefore,
the user should calibrate the flow meter and incorporate temperature sensor tolerance.
The supplied Thermistor sensor has an accuracy of ± 2
o
F. DIF represents the temperature
difference between two sensors. User can increase the accuracy of reading by adjusting the DIF
parameter. To calibrate the system, insert both S IN and S OUT in the same temperature (such
as ice-water glass), DIF should show “DIF 0” for exact temperature reading. If it is not zero,
accept the difference for better accuracy. This difference will be used as a correction value for
energy calculation. The energy calculation becomes more accurate at temperature range that this
reading adjustment is made.
BTU CL
Sets the BTU meter's counter to zero
CLEAR BTU meter's counter is zero
E