17 march 2022

SUCCESS STORY: AKOGAS NDIR – Reduction of Refrigerant Gas Leaks

0. Executive summary
0.1 Objectives
  • Reduce refrigerant gas leaks
  • Improve energy efficiency
  • Reduce tonnes of CO2 Equivalent emitted to the atmosphere
  • Reduce leak location and repair time
  • Improve the condition of the system and extend its operational life
  • Improve product condition
0.2 The solution

AKOGAS NDIR, combined with the AKONET.Cloud monitoring system, is a solution for monitoring and early detecting gas leaks that facilitates effective and preventive maintenance of refrigeration systems, resulting in huge savings in terms of gas leaks, energy efficiency and maintenance, as well as ensuring the proper preservation of stored products.

0.3 Results
  • 95% Reduction of Gas Leaks
  • 496 kg of Gas saved
  • 35% reduction in electricity consumption
  • 364.000 kWh saved per year
  • 90% reduction in leak location time
  • 11 Month Payback
1. Introduction

AKOGAS NDIR is AKO’s family of gas leak detectors, specifically designed to yield savings by detecting gas leaks early. These detectors incorporate nondispersive infrared (NDIR) sensors, which are characterised by:

  • High sensitivity: Being able to detect leaks as low as 1ppm, or 0.3g/h.
  • High accuracy: The reading provided is 95% accurate.
  • High selectivity: Thanks to NDIR technology, they only detect the refrigerant gas present in the system and are not influenced by other gases or substances such as ethylene, alcohols, solvents, fermentations, lye, etc., thus completely preventing false alarms that are common in other technologies such as semiconductor technology.
  • Great sturdiness: Its design has been specially engineered for industrial environments, with a robust enclosure and IP68 tightness (the greatest enemy of gases detection is humidity).
  • Built-in communication: Either via MODBUS cables or via NB-IoT (industrial, fully wireless technology with high signal strength), the equipment can be connected to the AKONET.Cloud monitoring system, which continuously monitors the system and triggers alarms in case of exceeding the configured leak thresholds, provides useful information to locate the leak earlier, categorises them, and generates automatic reports to evaluate the status and evolution of the systems.
1.1 Fast and easy installation

Just power the detectors at 12-24 VDC and perform a zeroing by using nitrogen. It is not necessary to calibrate the equipment, as they are factory calibrated. The detectors can operate autonomously, or connected to an AKOGAS or AKOSECURE alarm station (Alarm stations combined to trigger gas detection and locked man alarms), as shown in the image below:

Once the supply is connected, the installation wizard starts, which will guide you through a few steps to fully configure the equipment. As soon as power is supplied, the device will display ‘InI’ on the screen. If the detector is connected to an AKOGAS or AKOSECURE alarm station, define the Value as ‘1’; and if it is powered autonomously, choose the Value as ‘2’ by means of the keyboard.

In the next step, you will be asked to define the gas to be detected within the following:

Illustration 1: Types of Detectors Supply.

After doing this, the equipment would be completely configured. Once everything has been configured, the only thing left to do is to reset the reference value (not gas) properly.

If you want to connect the equipment via MODBUS, you can connect it directly to our AKONET.Edge communications gateway.

If it is connected via NB-IoT, there is no need to perform any additional task, since by means of this technology each detector communicates directly with the AKONET.Cloud without the need for routers, gateways, etc., making the installation much easier and cheaper.

1.2 Reduction of gas leaks and time spent in locating them
  • They detect leaks from 0.3 g/h. This way, you can be alerted at the very moment the pore starts to form, long before the leak becomes a major issue, not only because of gas costs, but also because of the reduced energy efficiency of the system and the risk posed to the preservation of stored products.
  • The system constantly sends alerts and highly valuable information for the proper maintenance of the system. Among others, the following stand out:
    • How much: The system will constantly indicate at what speed each point of the system is leaking, not only in ppm, but also in g/h. But it will also provide an estimate of the number of kilos of gas that will be lost in a year if the leak is not acted upon, and the percentage of gas that will be lost throughout the system
    • When: It will also indicate the time zone and days of the week when the leak is most active, making it even easier for it to be located.
    • Where: As it is a direct detection system, it will be always apparent at all times at what point or points of the system the leaks are occurring, reducing once again the localisation times.
  • It also provides a general overview of the system, providing information at all times of all existing leaks and allowing all of them to be tackled in a single intervention, reducing maintenance and associated travel costs
Illustration 2: Indicators associated with the leak shown by the system.
1.3 Improved energy efficiency, product care, and system handling

A leaky system implies not only a significant penalty due to the cost of lost gas, but also an equally significant decrease in energy efficiency and wear and tear of its components.

The relationship between the increase in electricity consumption and refrigerant gas losses in a refrigeration system is shown in the chart below:

Illustration 3: Relationship between a gas leak and the increase in electricity consumption of a refrigeration system.

As can be seen, a leak rate of 20% in the system (load at 80% of nominal value) implies a 15% increase in electricity consumption. This effect is because the fact that a system with an inadequate gas level is forced to ‘work’ longer to reach the desired temperature. At a very high leak rate, the system is unable to exchange heat and, in addition to the high cost of the leak in terms of gas and electricity, there will be a very high risk of jeopardising the preservation of the stored products, thus increasing shrinking and losses. The following chart shows the importance of detecting leaks as early as possible:

Illustration 4: Relationship between the costs associated with a leak, and the time it takes to detect and repair the leak.
2. Results

After one year of operations, the following results were obtained, which remain stable over time:

Illustration 5: Results in percentage of leak and electricity consumption reduction.

As the chart illustrates, the leak reduction achieved was 95%.

Similarly, the reduction in extra electricity consumption due to leaks was also 93%, which in turn means a 35% reduction in the electricity consumption at the entire refrigeration system.

In absolute terms, this produces the following results:

Illustration 6: Annual Savings in Kilos of Leaked Gas.

In energy saving terms, the following results were achieved:

Illustration 7: Annual saving in electricity consumption.

Written by: José María Cabria, In charge of Prescription and Pre-sales

Contact to our expert: jmcabria@ako.com