Method of operating a transport refrigeration system
First Claim
1. A method of monitoring a transport refrigeration system which conditions air returned from a cargo space via commanded cooling and heating modes, as required to hold a predetermined set point temperature, and discharges the conditioned air back into the cargo space, with the system having sensors for monitoring the temperatures of the return air, discharge air, and ambient air, characterized by the steps of:
- providing an algebraic difference Δ
T between the temperatures of the return air and the discharge air,selecting parameters for comparison with Δ
T as a function of the ambient temperature and the return air temperature,and comparing Δ
T with the selected parameters to detect a malfunction in the operation of the transport refrigeration system, regardless of temperature of the return air relative to the selected set point temperature.
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Accused Products
Abstract
A method of monitoring a transport refrigeration system which is effective regardless of the temperature of a served space relative to a selected set point temperature. Different "windows" of acceptable and marginal performance are provided in the form of different minimum magnitudes of ΔT, i.e., the algebraic difference between the return and discharge air temperatures, as a function of ambient and return air temperatures. The transport refrigeration system is thus monitored at all times, during both cooling and hot gas heating modes, and also including during initial temperature pull down of the cargo space, enabling an early warning to be generated for a marginal performance, and an early shut down to be initiated for unacceptable performance. In a preferred embodiment, a maximum value of ΔT is also provided, which, if exceeded by the actual ΔT, indicates a restricted air flow in the cargo space.
41 Citations
21 Claims
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1. A method of monitoring a transport refrigeration system which conditions air returned from a cargo space via commanded cooling and heating modes, as required to hold a predetermined set point temperature, and discharges the conditioned air back into the cargo space, with the system having sensors for monitoring the temperatures of the return air, discharge air, and ambient air, characterized by the steps of:
-
providing an algebraic difference Δ
T between the temperatures of the return air and the discharge air,selecting parameters for comparison with Δ
T as a function of the ambient temperature and the return air temperature,and comparing Δ
T with the selected parameters to detect a malfunction in the operation of the transport refrigeration system, regardless of temperature of the return air relative to the selected set point temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification