Making The Grade

Cambridge Refrigeration Technology puts a CSR-40 unit to the test

Thermo King is sure its CSR-40 unit with scroll compressor and R404A refrigerant has the highest capacity and best temperature control of any container refrigeration unit on the market. But tooting your own horn isn't always the most effective way to get people to listen. So Thermo King turned a CSR-40 unit over to the industry's independent expert to hear what it had to say.

The highly credible, Cambridge Refrigeration Technology (CRT) located in Cambridge, England has been putting the world's major suppliers of container refrigeration equipment to the test for more than 50 years. The company uses its environmental test chambers – airtight cells able to maintain precise temperature environments – to test equipment. "CRT's test chambers, which are approved by Lloyd's Register and also by the UK's Department of Environment, Transport and Regions, can hold temperatures anywhere from minus 15 to plus 55 degrees centigrade and can measure temperature control within plus or minus a quarter of a degree centigrade," said Robert Heap CRT president.

To ensure the CSR-40 is meeting the standards to which it was built, the unit was put through the rigors of an environmental test chamber for more than five weeks of evaluation.

And what did Thermo King learn? There were only pleasant surprises. The CSR-40 not only met but exceeded expectations as far as temperature control, thermal temperature, temperature pull down and capacity were concerned.

Specifically, temperature control was examined at set points of – 1 degree Celsius and +13 degrees celsius – these are the most challenging and critical temperatures to maintain. Temperature control was then tested by using a temperature-controlled heater and fan placed inside the insulated container.

A temperature differential was maintained between the outside and inside of the container. Once a stable condition had been established, the power required to maintain the temperature differential was measured. The thermal result was then calculated for temperature differential.

The tests concluded that the CSR-40 had a maximum temperature deviation of .25 degrees C above set point, three times less then its largest competitor.

In addition to temperature differential, CRT measured floor spread. Sensitive products such as bananas, which easily diminish in quality if temperatures fluctuant even by a half-degree, depend on a tight floor spread. Variances in floor spread create variances in the product temperature compromising product quality.

Each CSR-40 equipped container that was tested had 20 "T" bar floor channels. The delivery air temperature was measured at 12 feet out to determine floor spread. The graphs (at right or left depending on layout) depict both CRT and Thermo King testing of floor spread with the Fresh Air Exchange opened and closed.

Test results show the Thermo King unit had one-third the temperature deviation of its largest competitor – an important discovery because the more precise the temperature across the floor spread, the closer the temperature of the product will be throughout the container.

"The magnitude of this testing provides Thermo King with a true evaluation of the CSR-40's performance throughout all the tested ambient temperatures and set points," said Steve Bryant, Thermo King global director, product marketing, container.

CRT offers a range of services that include taint testing, evaluation of new refrigerants, temperature surveys and performance assessments. CRT's area of expertise is transport refrigeration and Thermo King plans additional product testing late next year.