Simplified mass balance method: An accurate way to track refrigerant emissions

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Courtesy of Verisae

With the simplified mass balance method, current levels of harmful refrigerant gases or other chemicals that harm the environment, such as hydrofluorocarbons (HFCs) and chlorofluorocarbons (CHCs), can be calculated and work to better predict of future levels of accumulated emissions formulated.

This emissions information enables environmental scientists and government regulators to better evaluate the rate of global climate change based on the usage of refrigerants and the related carbon emissions that contribute to the increases in greenhouse gases (GHGs).

A simplified mass balance method is used when determining the difference between the starting amount of a substance, such as refrigerant gas, and the end amount. The time period most commonly used is a calendar year. Consider this a similar concept to an accounting year for an organization’s taxes. This emissions related calculation determines how much of the harmful chemical was used in daily operation and how much was discharged into the environment.

The equation used for the simplified mass balance method adds the amount of refrigerant gas or other harmful chemicals that enter a process, such as a HVAC-R system, plus the different ways in which those chemicals are used, such as waste, vented during servicing, breakage of the system, or accumulation as reserve stockpiles. This equates to the final amount of refrigerant gas entering the atmosphere that leads, in concert, to the depletion of the ozone layer and increased release of high global warming potential refrigerants.

Using refrigerant gas as an example, the calculation takes into account the starting amount, its transformation throughout the entire cooling process, and the waste amount that required end of year accounting and reporting to a government body like the U.S. Environmental Protection Agency (EPA) or the California Air Resources Board (CARB).

By using a mass balance method, a facility is tracking the amount of substances used for a specific function in a very systematic and process driven way. This enables tracking and accurate data management down to the pound threshold across an entire organization if needed. It is broken down by how much enters the system, how much leaves the system and how much is stored within the system. This approach is used when it is necessary to account for pollutants.

The improvements in operational efficiencies will fully out-weight the incurred overhead of more refined business processes when an organization considers the increased cost of refrigerant gases painted against the backdrop of phase out schedules, the mandatory reduction of greenhouse gases, and the looming future of a carbon cap and trade system.

The mass balance method is required by the EPA to monitor and track chemicals that have been identified as harmful contributors to air pollution, the deterioration of the stratospheric ozone layer, and to increased, negative effects on global climate. These chemicals include chloroflurocarbons, hydrofluorocarbons, methyl bromide, halons, methyl chloroform, and carbon tetrachloride; essentially all of the substances tracked under The Montreal, Kyoto Protocols and future environmental regulations being drafted within the United States.

The simplified mass balance method is critical in designing and analyzing environmentally, damaging processes, such as refrigerant gas usage, as it moves its way through refrigeration, air-conditioning, or heating, ventilation and air conditioning systems. Simply put, whatever substances or chemicals enter a system must be accounted for, including what leaves the system and what accumulates within it. Therefore, in simple equation form, the “Inputs = Outputs + Accumulation” through system use or process operations.

Under the simplified mass balance method, facilities report the venting and use of refrigerants by providing data that includes their total inventory at the beginning and end of the specified reporting period, purchases of refrigerant during the particular time period, and capacity changes that occurred in the associated reporting time frame. This information is needed for each refrigerant type at all locations of a company or facility and across all systems containing refrigerant gases.

It has also been noted that accurate refrigerant inventory tracking is of high priority to organizations that maintain stockpiles of refrigerants on and off site. The mass balance method takes into account all harmful substances under control or owned by an organization. Suffice to say, an organization must account for all substances they are legally obligated to track, manage, and report even though they may have passed this responsibility to a service provider or HVAC-R technician.

Several factors are included in the mass balance method. The number and types of cooling equipment used, the types of refrigerants used for each system, leak rates and total refrigerant discharge. The equation helps identify mass flows that might otherwise have been difficult to measure or were unknown, such as substances that evaporated, leaked out, or became part of a chemical reaction.

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