Refrigeration Gas Detection

Refrigeration Gas Detection Solutions – IGD

We have a long history in the refrigeration industry with countless refrigeration gas detection systems installed world wide protecting plant and personnel. Clients have chosen our addressable systems due to a wide ranging factors including; cost saving, flexibility, scaleability, IGD guarantee, IGD long life sensors and detection capabilities.

Choosing IGD as your gas detection provider offers you a range of benefits

• CO2 detectors Based on proven infra red technology.
• Ammonia detectors based on our new Ionic technology for long life and performance. (see article here)
• Housed in robust ABS enclosures 750 safe area detectors 
  
  

  Pictured: TOC-750 series addressable safe area gas detector. Sensor options for over 400 gases.

• or ATEX/IECEx zone 1 and 2 versions – 750X Variant.
  
  

  Pictured: 750X series addressable ATEX/IECEx zone 1 and 2 gas detector

• Features built in dust and drip baffles to protect sensors
• Can additionally be fitted with splash guards for wash down area use
• Easily installed, Sentinel+ technology digitally connects all system parts
• Automatic controller configuration on detector node discovery
• Controllers easily interface to BMS, SCADA and RDM systems
• Can be cloud connected and remote monitored
• Simple to fit, clear and easy to use
• Sampling detector (aspirated) versions for cold stores, spiral freezers and hard to reach areas
• A range of adaptors for application integration

Our refrigeration gas detection solutions are designed to be modular and scaleable to your site requirements. With massive cost savings of around 70% on installation alone compared to other systems on the market. Plus a range of connectivity options such as RDM.

Controller Options

• TOC-635 entry level systems can be used with up to 32 detector nodes. Featuring our industry first 1 click automatic system setup. Reducing installation and commissioning costs.
• TOC-650 and 750 based systems for larger plant up to 128 Detector nodes.

All systems use IGD’s Sentinel+™ technology designed specifically for gas detection and we have a 10 year warranty on all electronic parts (non-consumable).

Replacement with Greener Alternatives

Both local and global legislation and agreements have led to a move back to ‘older’ refrigerants as ‘greener’ alternatives. The older alternatives, Ammonia, Hydrocarbons and CO2 have all been used historically for refrigeration but were dropped in favour of the now banned CFC’s. Improvements in technology, materials and our general understanding now mean these materials are finding increased use in the refrigeration industry.

Refrigerent	ODP	GWP (1)
Ammonia R717	0	0
Carbon Dioxide R744	0	1
IsoButane R600a	0	3
Propane R290	0	3
Propylene R1270	0	3

As can be seen by comparing table values these ‘older’ refrigerants have no ODP and very low or zero GWP.

Ammonia is both highly toxic and flammable. The hydrocarbons, R600a, R290 and R1270 are flammable and are listed as having a narcotic effect at higher concentrations.

Carbon Dioxide on balance would therefore seem to be the ideal refrigerant choice but it is also not without its own problems.

 Carbon Dioxide (CO2) R744 as a Refrigerant

There is nothing new in the use of CO2 as a refrigerant. Carbon dioxide was widely used at the start of refrigeration around the year 1900. Unlike ammonia, however, it more or less disappeared when the (Hydro)ChloroFluoroCarbons ((H)CFCs) were launched. After being re-introduced as a refrigerant around 1990, CO2 has become an important alternative in replacing environmentally harmful refrigerants such as CFCs, HCFCs and HFCs

From an initial look at the thermodynamic properties of CO2 it would appear to be a poor choice for a refrigerant. Carbon Dioxide however does have some unique thermo-physical properties.

• Low Viscosity
• Relative insensitivity to Pressure Loss
• Good Heat Transfer Coefficient

Practically CO2 can deliver high performance as a refrigerant with advantages of:

• better heat exchange
• low pumping power when used as a secondary fluid
• low condensing pressure in winter or colder climates.

The efficiency of CO2 as a refrigerant depends more on application and climate than other refrigerants. As condensing (ambient) temperatures increase there is a corresponding decrease in efficiency with all refrigerants. This effect is greater with Carbon Dioxide.  CO2 is amongst the refrigerants with the steepest drop in efficiency as ambient temperatures increase.

CO2 has a high energy content so where this can be recovered for secondary heating or similar applications the overall system efficiency becomes very high.

Sustainable (ODP=0, GWP=1)	Less efficient at high outside temperatures
Cost effective	High Pressure System
High Volumetric Performance
Non Flammable

 

CO2 in Commercial refrigeration

Commercial refrigeration is that used by retail outlets to display, hold or prepare food and beverages purchased by customers. Examples include refrigerated display counters in supermarkets, refrigerated vending machines, water coolers/heaters and ice generating machines. Commercial refrigeration consumes approximately 28% of worldwide refrigerants. This makes the sector the second largest user of refrigerants. In 2002, commercial refrigeration was responsible for more than 185 000 tons of leaked refrigerant into the atmosphere or 37% of total refrigerant leaks. Energy utilisation in this sector is high necessitating a need for efficient refrigeration systems.

Until recently Carbon Dioxide applications in commercial refrigeration were not considered viable. Extensive research and development has realised effective use of Carbon Dioxide as a refrigerant. Factors such as safety requirements, extra tax on HFC systems and limitations on the maximum amount of HFC charge that can be used on a single system were the main reasons for Carbon Dioxide acceptability in commercial refrigeration. As the world accepts the use of Carbon Dioxide in supermarkets, studies show that its associated costs and energy consumption are comparable to other conventional refrigeration systems. It has been suggested that Carbon Dioxide systems are the dominant technology of the future because of their good thermophysical and safety properties.

Carbon Dioxide technology is even now being used in stand-alone bottle coolers and both hot and cold vending machines. Major investment in the light commercial sector is directed to Carbon Dioxide technology, with more than 85 000 units in operation worldwide.

Risks When Using CO2 as a Refrigerant

in the UK Carbon Dioxide falls under COSHH legislation as a substance hazardous to health and is listed on UK Health and Safety publication EH40. As such, to show compliance under COSHH, an operator would need to have carbon Dioxide detectors installed. If you are not monitoring the atmosphere you do not know if a dangerous leak is developing. Carbon Dioxide is heavier than air at room temperatures. This means it can be difficult to disperse leading to pockets of high gas concentration. Remember the gas is leaking at 100% concentration.

Hydrocarbons (HC’s) used as Refrigerants

The following hydrocarbons are commonly used as refrigerants:

• R290 Propane
• R600a Isobutane
• R1270 Propylene

A number of other hydrocarbons, such as blends containing ethane, propane or butane, are also used as refrigerants.

Propane has long been discussed as a replacement for CFCs and especially R22 (HCFC). Except for its high flammability Propane has very similar properties to R22. Propane has a long history in refrigeration however, its flammability has limited its use. Isobutane (R600a) was introduced in household appliances in some parts of the world from the start of CFC phase out. Propane was introduced later and replaced R134a, R22 or R404A in a wide range of appliances.

Propane (R290) and isobutane (R600a) are inexpensive and easy to obtain. Despite their flammability, they are easy to handle. Worldwide millions of household refrigerators work with isobutane as a refrigerant.

Hydrocarbons of this type also work in commercial refrigeration. They find common application in refrigerated counters and ice machines, or in air dehumidifiers and heat pumps.

HCs are also suitable for other applications for example air-conditioning systems where carbon dioxide reaches its limits when outside temperatures are high. Having similar thermodynamic properties to synthetic refrigerants, systems follow the same designs. It must be noted that higher safety requirements must be observed, as HCs are flammable.

Despite the similarity in system design, refrigeration systems using hydrocarbons require, for example, different compressors and safety precautions than those using synthetic refrigerants. It is therefore not possible to replace, for example, R134a with hydrocarbons in an existing system. In addition to safety aspects resulting from the flammability of HCs, the oil used in the compressor plays an important role. Larger plants also require systems for flammable gas leak detection. The additional costs of the system arising from the required safety technology are usually offset by the lower refrigerant costs.

Propane R290  IsoButane R600a

Sustainable ODP=0 GWP=3	Flammable and a Narcotic
Non Toxic	Additional Safety Standards (ATEX)
Works at low Pressure

 

Risks When Using Hydrocarbons as a Refrigerant

R290 Propane, R600a Isobutane, R1270 Propylene are all flammable and are all heavier than air. Any leaks will not disperse easily, early detection of leaks is therefore essential. Refrigeration plant  using hydrocarbons will usually fall under DSEAR regulations (Dangerous Substances Explosive Atmosphere Regulations).

Ammonia (NH3) as a Refrigerant

Ammonia (NH3) has long been used for large scale refrigeration plant.  Ammonia thermodynamic properties  outperform most synthetic refrigerants.

Ammonia (R717) has an ODP and GWP of zero, it is a particularly climat-friendly refrigerant and also a very efficient one. It has excellent thermodynamic properties, reflected in very low operating costs for refrigeration technology. It has consistently been used in the food processing plants, the beverage and airy industry, as well as in breweries and cold stores.

Ammonia is the first choice for systems with refrigeration/heating capacities of about 300Kw.

Sustainable ODP = 0, GWP = 0	Toxic
Cost Effective	Flammable
Excellant Thermodynamic Propertiies	Additional safety Measures (ATEX)

Risks When Using Ammonia as a Refrigerant

Any leaks in an Ammonia refrigeration system must be reliably detected.  Ammonia is toxic at low ppm levels and flammable in higher concentrations. Larger Ammonia plant will usually fall under DSEAR regulations (Dangerous Substances Explosive Atmosphere Regulations) and also COSHH (Control of Substances Hazardous to Health).

Ammonia, when a gas, is lighter than air but can exist as a super cooled vapour which will initially be heavier than air. Detection is usually required both at low and high level to be effective.