Hot and cold air to cost more
Aug. 29, 2011
by Anne Giesecke
The Environmental Protection Agency is continuously proposing new air rules. The new rules will increase the number of bakers and snack food manufacturers who will be required to buy air pollution control equipment such as catalytic oxidizers, bag houses and ammonia refrigeration systems.
Catalytic oxidizers destroy alcohol (called ethanol) emissions from baking yeast fermented products. In addition, as consumers demand more hot, spicy and savory seasonings — think asiago cheese — these new combinations and options may cause strong aromas to be emitted. In some areas, odor emissions require air control equipment, often a catalytic oxidizer. The purchase and installation of a catalytic oxidizer costs about $500,000 in capital and $25,000 a year for operation.
Particulate emissions are dust from ingredients such as flour and also must be controlled. Bag houses or socks are used to control particulate emissions. These cost about $5,000 in capital and $8,000 a year in operation.
Ammonia refrigeration systems replace chemicals that are ozone depleting substances and are often lower in price but ammonia is hazardous.
Last year the E.P.A. proposed strengthening the national ambient air quality standards for ground-level ozone, a component of smog. The concern for bakers and snack food manufacturers is yeast produced ethanol. The standards are still under review. However, states need fees and are moving forward in anticipation of more stringent E.P.A. requirements.
The E.P.A. is proposing to strengthen the 8-hour ozone standard to a level within the range of 0.060-0.070 parts per million reduced from the existing 0.075 p.p.m. This will mean that up to 85% of the counties currently monitored by the E.P.A. would fall into “nonattainment” status by not meeting the air-quality ozone standards and triggering a plethora of federal and state controls.
Ozone concentrations are averaged over 8-hour periods. The fourth-highest 8-hour value at a particular monitor in the most recent year is averaged with the fourth-highest 8-hour values from the previous two years. This produces a three-year average. For compliance the three-year average must be less than or equal to the level of the standard.
Under the Montreal Protocol the United States agreed to phase out all ozone depleting substances (ODS). The first to go were the most destructive class known as chlorofluorocarbons (CFCs). Next were hydrochlorofluorocarbons (HCFCs), such as R-22, which are being phased out yearly until 2020. The use of these chemicals is legal, the production and import on virgin material is illegal.
Hydrofluorocarbons (HFCs) are non-ozone depleting fluorinated greenhouse gases intentionally-made and used in various applications. HFCs such as R-134a and R-404A are alternatives to ODS. HFCs when leaked to atmosphere trap heat and are considered one of the six global warming chemicals in the Kyoto Protocol. The United States is not a party to the treaty but some states such as California have passed legislation covering HFCs.
Hydrocarbon (HCR) substitutes are being encouraged as replacements because they have a low global warming potential (GWP). For example, in 2010, the E.P.A. issued standards for greenhouse gas (G.H.G.) emissions from passenger cars and light-duty vehicles for model years 2012 through 2016. According to the E.P.A., the regulation included an option for car manufacturers to earn credit toward G.H.G. emission standards by switching from the current automotive refrigerant, HFC-134a, to a refrigerant with a lower GWP. General Motors has announced its intent to start manufacturing some models using a fluorinated hydrocarbon (HFO) HFO-1234yf (3,3,3,3-Tetrafluoropropene) in their 2013 model year, to be built in 2012 in the United States.
Currently, commercial chillers are expected to use microchannel heat exchangers or ammonia. Sometime in the next 10 years blends of refrigerants with low global warming potential will be available. Freezers will use hydrocarbons, carbon dioxide or HFOs. Transport refrigeration alternatives during the next 10 years will shift to hydrocarbons, ammonia and blends of refrigerants with low global warming potential.
Ammonia in applications
Ammonia refrigeration systems are common now but have limited application because of the hazard potential of a leak and of an explosion. For example, fire departments and local permit agencies will deny ammonia systems when they are proposed in proximity to hospitals, schools or other sensitive populations.
Ammonia is being used to cool carbon dioxide in carbon dioxide cascading refrigeration systems. Ammonia also is used to chill glycol. Ammonia is limited in the amount needed and confined to an engineering room.
Pressure and temperature are issues for all refrigeration systems. Energy savings may be achieved for all the refrigeration systems with attention to fans, pumps, and compressors.
Changing rules for production air emissions and refrigeration systems need to be part of a long-term budget strategy.