VRF’s and Solar HVAC Systems;

These two different systems seem to be at very different stages of the game, but are they? They’re going to be competing for the same energy credits and ultimately combining features so we need to talk about them together. For years we’ve been installing ductless split systems, since the early 1990’s. The very basic systems never had more than two indoor sections to one outdoor section. They had limited heating ability in the heatpump mode and not much in the way of electric heat. They did a good job in the cooling mode especially where there was a constant heat load. They couldn’t heat in one indoor section and cool in the other at the same time. The new systems have the ability to have multiple indoor sections and can simultaneously heat or cool as required. It took a little bit of time for the engineering community to take these systems to the drawing board because there was not a good rating system to compare efficiency. They were mainly used for renovation type projects in hard to modify buildings. That’s all changed.

ModernControls has been involved in the installation of several of these systems, manufactured by several different companies. We recently completed the installation of an LG HVAC system in a design build job for a private school. We are currently installing an LG HVAC system for a new out of the ground bank branch. We’re not the first to install one of these in a cookie cutter design building for this company. The low operating cost and the ability to have multiple setpoints to keep employees and customers comfortable was the reason they chose this type of system. With the addition of an energy recovery unit and demand ventilation these will be very efficient buildings. We just had preliminary approval of a design build LG HVAC system for a college law library, lecture rooms and office area. One space is a mock trial room set up for distance learning and video recording. This space will have what appears to be a conventional ducted air handler for sound attenuation. The rest of the spaces will use a ceiling mounted cassettes. The building will also utilize an energy recovery unit and demand ventilation controls. The installation cost is not out of line with a direct replacement of the existing system. The advantages agained are lower operating cost and individual space temperature control. Expect to see these systems take over a good portion of new installation and design build market.

The next big change will be solar panels tied directly into the residential and light commercial HVAC units. The big name in the market place right now is Lennox; but every manufacture will have to put out something to stay competitive. Solar is not new but this type of set up is so superior to any other way to “go solar” I’m surprised it took so long for someone to come up with it. The largest electrical consumer in most buildings is the HVAC system, it makes perfect sense that this should be the primary connection to the solar generation of power. If the wires are large enough to bring the power out to the unit than they are large enough to bring the unused power into the building when the unit has cycled off. The power management is handled at the outdoor section or rooftop unit. Imagine not paying for air conditioning when the sun is shining. The ease of installation in new and retrofit jobs will make these systems popular.

Now imagine combining the two, variable flow refrigeration systems and solar powered HVAC systems. Ease of installation, reduced operating cost and individual space setpoints. Solar panels have become common place, the technology is sound and installation cost is reasonable due to the short payback period. Variable flow refrigerant systems now have a reliable rating system that shows a substantial payback compared to conventional systems. They’ve been on the market for years and have several manufacturers with good reputations. The time has come to invest in the training and equipment to design, install, and service these systems.