Be a cool Wethead
By Bob “Hot Rod” Rohr
Wethead is a term that has been applied to folks who are involved in hydronics, that is mechanical systems which transfer energy with a fluid− water, for the most part. Since the beginning of time, hydronics has usually been linked to systems providing mainly heat. But in reality, hydronics has many other applications, including cooling via the use of chilled fluids.
As time goes on, we evolve and learn more about the environment in which we live. In many places, keeping a space comfortable to work or live in includes the need or desire to both heat and cool the living and working spaces. Taking it a step further, we should be talking about and learning about comfort systems. This would involve maintaining a comfortable temperature throughout the year, through efficient heating and cooling while making sure the indoor environment is healthy.
To this end we would look at controlling humidity, dust and particles, and odours in the space. This would fall under the banner of indoor air quality (IAQ). All components need to be selected and sized for the appropriate applications. Often, the budget will dictate how far the consumer will go to provide the best IAQ system in a residence. However, when the owners understand the benefits of your product offering in terms of comfort, safety and IAQ, the budget tends to expand.
We should talk about and offer our customers “comfort” systems. Under this banner we look at heating, cooling and IAQ, and apply the best arrangement of system components from the hydronic and HVAC worlds.
Being in the training side of the industry for the most part now, I encourage all readers to focus in on some of the latest technology and product offerings. If one good thing has come out of the COVID-19 lockdown it is online training offerings. Every brand I know has stepped up their game to make it easy to continue your education. It could be a quick podcast, a webinar or Zoom meeting, or hybrid training which involves multiple screens. The instructor is in front of a live piece of equipment and the student talks them through the repair. With a good GoPro and some lighting it can be an excellent way to get hands-on training − without even getting your hands dirty.
Where do Wetheads fit in?
Just as we do with a heating system, an appropriate design should be performed both for new or replacement work. The first step would be a heat load/heat gain calculation. On an existing home, a blower door test would help identify areas where infiltration could be adding load.
Doing the load calc and infiltration test may point the owner to a few “shell” upgrade opportunities before jumping into equipment sizing and selection. For instance, updating and insulating leaky windows, doors and roofs. The best money spent is addressing and lowering the load. This will not only reduce the upfront cost of the components, but ongoing energy consumption and related costs will be reduced as well.
Generally, we deal with cooling loads by blowing chilled air around the space. Ducted forced air systems are the most common application. Small areas may be handled with window shakers, or mini split systems, or in some cases portable AC units. With a forced air method of cooling you get the added benefit of filtering the air. I suspect one of these methods will continue to be the predominate way we cool spaces.
Ducted forced air is a known commodity. A broad selection of brands and sizes are available. The HVAC trade is well established and there are plenty of training opportunities both private and manufacturer sponsored.
Always take the time to learn of the features, benefits and applications requirements of the products you propose or sell.
If you understand, or your customer does, that the climate is changing − we are seeing hotter and longer summer seasons − then Wetheads are well served to add HVAC components and options to their overall offerings. Be the “cool” guy or girl in your service area. After getting yourself well trained and prepared, offer the latest technologies to service their comfort needs.
A look at options
We commonly see hydro air systems being installed. These involve an air handling device with a hot water coil inserted into the ducting system. This allows a boiler-based system to supply the heating via the same ducting as the cooling. It brings in a boiler or other hydronic heat source to keep the system “wet.” In some cases, a single contractor installs the hydronic and air side or separate trades may work together to assemble the hydro-air systems. With a cooling coil included you can heat and cool from one metal box. Humidity could be added as well as numerous filtration options in a ducted system.
Mini splits entered the market through the HVAC channel. The quick and easy installation also lends itself to the plumbing trade. Assuming your licence allows both, and you have been trained in proper sizing and installation, servicing mini splits is a good service to offer. Mini splits go well with radiant heat systems in many cases.
Another technology worth investigating is a hydronic-based system using the embeded PEX tubing to cover the heating load and all or some of the cooling load. Currently, this is only a niche market opportunity, though a potentially very lucrative one. This may involve using the tube, installed in a slab for example, to circulate chilled water. Ceiling distribution is possible with chilled beams or suspended ceiling grids, which have chilled water circulating through them. In arid climates you may be able to cover the cooling load with just chilled surfaces. The dewpoint needs to be monitored to avoid “sweating” of the surfaces. In such cases there may need to be some additional air circulation and dehumidification.
What is most exciting to me is the growing offering of air to water heat pumps (A2WHP). This type of equipment is able to supply fluid that is either warmed or chilled. From one component, powered by electricity, we have the ability to heat and cool, and in some cases, cover some DHW load. This brings or keeps the hydronic contractor at the table. It can also address areas migrating toward fossil fuel regulations.