Mike Creamer of Business Edge has discovered an electronic system analyser that also takes the sweat out of service and commissioning work
You must have been faced with that situation where your ac or refrigeration is not performing properly and you’re not sure exactly why. You have taken pressure readings and a few temperature readings and applied the usual logical deductions but the things are still not right. For example, the equipment is failing to hold the desired room temperature; or the client is complaining of increased energy costs in a large building or large refrigeration load application. How do you truly get to the bottom of the problem?

Whilst you are trying to read temperatures and pressures, they keep changing with the refrigeration load and ambient condition. It is difficult to run around recording them all under these circumstances and then you have to perform a quick calculation to establish superheat and sub-cooling.

If it is R407C or a refrigerant with similar glide characteristics, it is ten times worse. Faffing around with glide and superheat in relation to this can be really confusing and it is easy to make mistakes. Even then, do you really know how efficiently the compressor is running? Is the system COP within limits? Would you even know what those limits are? Then, what about compressor efficiency? What is it at the moment and what should it be?

In my experience, there is a wide gap between what goes on at the manufacturing/design level of ac and refrigeration systems and the applications engineering level. Then there is a gap between applications engineering and the commissioning and service engineering levels. For example, the senior designer at a major compressor manufacturer will be fully aware of the characteristics of its scroll compressor model X, but the manufacturer using this within his condensing unit will have a different set of parameters representing normal operation.

The condensing unit is then used by an m&e design company/contracting company in conjunction with an evaporator within an ahu and the characteristics of this system are different again. Indeed, the operating performance of this type of system will not be known until it is actually installed, commissioned and run-tested.

The point I am trying to make is summarised by the following:

1. It is currently impossible to derive all the essential parameters of a running air conditioning or refrigeration system on site unless one goes to extraordinary lengths to hire complicated analytical equipment and bring all the data together for subsequent calculations and analysis work to be performed.

2. A system may appear to be performing well when a spot check is conducted. However, experience shows that cyclic behaviour occurs on many faulty systems. Such behaviour can occur over 20-second cycles or several minutes and it is thus possible for the engineer to miss these events when conducting spot checks.

3. Systems that run 24 hours will run very differently during the night. This is also true when there are substantial changes in load. The effect of erratic, faulty or incorrectly set controls will only become evident if systems are monitored over a long period of time.

4. It is unrealistic to expect the majority of commissioning and service engineers to perform complicated calculations on site using limited instrumentation of questionable accuracy.

5. Systems that are running inefficiently and consuming unnecessary additional electricity cannot be identified. This excess energy leads to unnecessary global warming and higher energy bills for the customer.

It is the last of the above points that concerns me most. I have visited so many installations ranging from close-control and critical ac systems, data rooms, refrigeration systems and supermarket refrigeration. We have literally thousands of compressors being produced every week for new equipment (and replacements). It is clear that the air conditioning and refrigeration industry is a colossal market and represents a large percentage of energy consumption throughout the world.

Indeed, the majority of buildings that I visit in my trouble-shooting and consultancy work incorporate cooling systems that are the single biggest consumer of energy within the building. If such systems are not set up correctly, the energy consumption consequences are enormous and all of this can hang on just how well the system was charged, a simple valve was set, a low ambient controller setting was made and so on. However, there is now a solution to this problem. This consists of a portable analyser which is capable of monitoring every salient aspect of any type of air conditioning or refrigeration system. It contains all the necessary thermo-dynamic data for every refrigerant you are likely to be using. It will handle simple compressor/TEV/evaporator/

condenser systems or systems with multiple compressors, sub-coolers/economisers, heat recovery and so on. All you require is the correct system template.

Clearly, in order to measure the performance of any acr system, it is necessary to monitor the following: suction pressure, discharge pressure, superheat, sub-cooling and power input.

Once the sensors are connected to the system, the analyser will take instantaneous readings of all parameters at a variety of time intervals (5 seconds, 30 seconds, etc). It will then perform all the necessary calculations and display all the parameters on the screen of a connected portable PC. As soon as the first line of information appears, the refrigeration engineer can make immediate decisions regarding the operating performance of the system, sub-cooling, superheat, efficiency, capacity and so on. And, what is more you do not need to load the airflow, entering dry bulb/wet bulb, leaving dry bulb/wet bulb air conditions at your evaporator; and where water-based systems are concerned, you do not need to know that water flow rate or the entering/leaving water temperature.

The name of this product is ClimaCheck. The man who developed it, Klas Berglof, has been working on this technology for many years. In reality, the concept is simple, albeit the mathematics and the development of such a product are a little more complicated.

I have used this product for some time as it has proved essential for my trouble-shooting and consultancy work.

Our collaboration with ClimaCheck has been very successful to date and, as a result, have reached a joint agreement whereby Business Edge will be the sole UK distributor for the product. For more product information contact 02392 230007.