Each day we’re reading headlines about decarbonization ambitions for buildings while challenged with supporting day-to-day operational needs. Yet, we’re still tasked with delivering energy and cost reductions.
Given the magnitude of energy consumption and the importance to occupant/tenant comfort, HVAC systems warrant significant attention. There are a lot of options with new equipment and controls to drive energy use down and enhance overall comfort that are very impactful, when budgets allow. However, there are budget friendly options that should be considered now.
There are aftermarket products that restore lost performance efficiency, reduce loads on equipment and extend equipment life. A challenge is knowing which products really work and what can be trusted.
Refrigerant additives have been around for decades, solving several issues including improved thermal heat transfer, reduced frictional forces through enhanced lubrication, acid scavengers, water displacement, stop leaks, and the list goes on.
Over forty years ago, some of the first refrigerant treatments were formulated, with varied results. The principal objective was twofold: enhance the heat transfer from the refrigerant to the heat exchanger coils and reduce friction on the compressor moving parts.
How To Reduce Compressor Friction And Keep It Low
Industry offered improvements to refrigerant oils, building on synthetic oil development
HVAC systems include oil to lubricate the compressor mechanical moving parts with mineral oil being the old standard, used for decades. Older systems with R-22 refrigerant, as well as other types, use mineral oil. This oil, made from naturally occurring crude petroleum oil, is prone to breakdown over time from wear and elevated temperatures. This means hermetically sealed compressors operating with the same oil as when originally built are running with greatly diminished friction protection. Friction protection longevity was greatly improved with the advent of synthetic oils, but even these oils can see diminished protection from wear and elevated temperatures.
Industry offered improvements to refrigerant oils, building on synthetic oil development. Two additives commonly found in gear oils include active sulfur with phosphorus, noted as Extreme Pressure (EP) gear oils. This same approach found its way to HVAC systems, adding materials that offered greatly improved friction reduction.
Some mistakes were made, such as using polytetrafluoroethylene (PTFE), best known as Teflon. Although PTFE has phenomenal lubricating properties, it is too large of a minimum particle size, creating havoc within expansion valves. Teflon also received scrutiny by researchers identifying adverse health effects. Today, there are several technologies promoting improved refrigerant lubricants, either as a direct replacement or as an additive to existing oils.
How To Restore Lost HVAC Performance Efficiency
The refrigerant oils that keep compressor moving parts running serves a second important role: acting as a seal to keep compressed refrigerant from escaping from the compressor and ending up in the oil sump. HVAC engineers allow and design for some oil to migrate through the refrigerant loop, the condenser and evaporator coils. More sophisticated equipment, such as chillers, have features to collect and return most of this oil. Simpler systems rely on the high velocity of the refrigerant to pull the oil through the coils and return it to the compressor. Inevitably, some oil remains as a film on the heat exchanger coils and slowly builds through the operational life of the equipment. The oil buildup continues to reduce the heat transfer efficiency between the refrigerant and the coil walls.
There have been numerous formulations brought to the market with few detailed accounts of chemistry specifics
An opportunity was born for creative individuals to invent formulations that would remove this efficiency robbing oil layer. Early design attempts sometimes led to more problems than the efficiency improvements were worth. Some chemistry mistakes included using solvents or other cleaning agents to aid in removing oil from heat exchanger tubing. This diminished the effectiveness of the refrigerant oil and led to shortened equipment lives.
There have been numerous formulations brought to the market over the past four decades with few detailed accounts of chemistry specifics. There are few patents in addition to product website information that offer limited details in the public domain, making it hard to trust the suppliers.
Today’s formulations offer greater opportunity for realized performance gains, especially given advances in material science. Nanomaterials have enabled several newer solutions to be developed. One such product employs graphene, which is known for its fantastic heat transfer and lubricating properties. Nanomaterials offer properties to enhance heat transfer, improve lubrication while negating concerns about excessive buildup within expansion valves. For example, graphene exists as a one atom thick nanomaterial.
Perhaps the biggest challenge to the use of nanomaterials was how to keep the particles in suspension over the life of equipment, something that most specialty chemical houses hold as trade secrets. Some products offered today boost refrigerant performance, stating altered boiling points. The performance is achieved by adding particulate that acts as nucleating sites. As material science continues to advance, we’ll see more products enter the market that also address changes in the choice of refrigerants and refrigerant oils.
How To Select The Best Additive For Your Needs
Make sure the formulation is compatible with your specific equipment, refrigerant and refrigerant oilWhen considering additives to reduce energy consumption for your HVAC refrigerant systems, your contribution to decarbonization, do your own due diligence and require validated performance efficiency improvements. Make sure the formulation is compatible with your specific equipment, refrigerant and refrigerant oil.
Given that many sales agents won’t divulge their respective chemistry (or don’t know it) and most individuals responsible for HVAC equipment aren’t chemists, look for credentialed validations and testing. Ensure the products have been evaluated against ANSI standard compatibility tests and performance validated to ASHRAE or other accepted industry standards.
What The Market Thinks Of Refrigerant Additives
Over the first few decades since the creation of efficiency improving formulations for refrigerants and refrigerant oils, there has been mixed market adoption. The early days of failed attempts with oil degrading use of solvents or the use of expansion valve clogging solids, left a lingering perception of “snake oil”. Only those businesses that took the time to sort through the offerings to find the truly validated products found success in reducing their HVAC energy use and an added benefit of extending the life of their equipment.
Today the market is better accepting of newer technologies, gaining distance to the old wild west days of unproven formulations. Trust is being earned for those businesses that offer professionally validated products that stand behind them with warranties.