Why is Commercial Water Source Heat Pump (CWSHP) technology the best kept secret in HVACR?
I have been preparing for a two week tour of the Pacific coast which will include a couple ‘Introduction to Commercial Water Source Heat Pump Heating & Cooling’ classes, (see www.ESPCOtraining.com for class dates, times and locations). I have had this class in my repertoire for a few years now and I felt it was time to overhaul it and freshen it up a bit.
I was surprised to find in my research of the subject that there is very little information about CWSHP available…I mean like close to nothing! Compared to the abundance of information available about geothermal, (the sexy version of water source), it really seems like CWSHP is a secret that needs to be told…and since I have never been any good at keeping secrets, I’m here to spill the beans!
Before I get into the nuts and bolts of CWSHP, let’s take a minute to look at what is the latest craze in HVACR right now…Variable Refrigerant Flow (VRF) ductless split systems. VRF is getting a lot of attention for many reasons, not the least of which is the fact the these systems can heat and cool at the same time…a wonderful advantage for commercial buildings where core, (interior), offices may require cooling when perimeter offices may require heating…all at the same time! VRF is fascinating technology but it’s not all fairy dust and rainbows…the technology is very complicated making the proper installation tricky and the equipment ain’t cheap!
There is an alternative to VRF that fulfills many of the same goals, (most notably simultaneous heating and cooling), at a fraction of the cost with proven technology that most guys my age, (old that is), feel comfortable with and has been around in its simplest form since time immemorial…you guessed it…Commercial Water Source Heat Pumps!
So how do these mysterious little anomalies work? Well, let me tell ya…
A Water Source Heat Pump is a self-contained water cooled packaged heating and cooling unit with a reversible refrigerant cycle. During the cooling mode, the tube-in-tube (coaxial) heat exchanger functions as a condenser and the coil as an evaporator. In the heating mode, the tube-in-tube heat exchanger functions as an evaporator and the coil as a condenser. A reversing valve is present in the refrigerant circuit permitting changeover from heating to cooling and vice versa.
Multiple WSHPs utilize a single hydronic (water) loop with a boiler or water heater as well as a cooling tower in the loop. The loop is often referred to as the ‘condenser loop’. The heat rejected by the units in the cooling mode is absorbed by the condenser loop and used to warm the units, (zones), calling for heat. A boiler or water heater is generally used for adding heat, (BTU’s), to the condensing water during peak heating periods.
The system also utilizes a water cooling tower to reject the heat energy from the condenser water loop during periods of high cooling demand.
In cold weather, the condenser loop supply temperature can be about 70°F with return temperatures around 64°F…the boiler / water heater is on, the condenser loop pump is on and the cooling tower is off.
In hot weather, the condenser loop supply temperature can be about 85°F with return temperatures around 95°F…the cooling tower is on, the condenser loop pump is on and the boiler / water heater is off.
In certain times of the year, (generally spring and fall), the system actually becomes ‘balanced’ where the condenser loop components, (boiler / water heater and cooling tower), are dormant, (off), and the WSHP units themselves do all the work. The units in the interior of the building where cooling is required reject their heat to the condenser loop water, (via the coaxial coil), which is absorbed by the perimeter units where heating is required. The only component of the condenser loop energized through this period is the loop pump which keeps the water flowing throughout all the WHSP units so units that are cooling and units that are heating can all work in concert with each other utilizing each other’s rejected BTU’s.
How cool is that? (pun intended)
These systems are universal in their applications throughout North America. I have conducted my class in Florida, New England, Canada and now the left coast. No matter what the climate, CWSHP can solve tough heating and cooling problems for commercial buildings of all sizes with relatively simple technology applied in a unique manner…what I like to call ‘good ole American ingenuity’!
Advantages of these systems beyond what I have already discussed are; the ability to ‘zone’ and the ability for those zones to adapt to changes in location, size and occupancy…i.e., one tenant moves out, another moves in who requires a different floor / wall plan within the space, the CWSHP system can be easily adapted to the new occupants needs.
A distinct advantage that these units have over ‘central ducted’ type systems is that since they do not share a common ducted system, any airborne contaminants which may be present in one zone is not transported via common duct to another zone, i.e., if the accounting department has the flue, the sales department won’t be effected.
Normally, multiple units serve an occupied space so there is built in redundancy so should one unit go down, there is another in the same space / zone providing some conditioned air until the down unit can be repaired or replaced.
…and speaking about replacement…
The ‘packaged unit’ concept of the CWSHP allows for quick change outs when required. This is great business guys…replacements units are available from my good friends at Comfort-Aire® that replace a wide variety of other manufacturer’s units and are available for quick delivery!
If you are at the AHR EXPO in NYC next week, drop by the Heat Controller / Comfort-Aire® booth #1607 and talk to the CWSHP pros from Comfort-Aire®!
Keep an eye on my website for a CWSHP class coming to a town near you in 2014. I will tell you this straight up about the class…it is not for the faint of heart! I go through the equipment selection process for new jobs as well as troubleshooting of both the water and refrigerant side of the system. You will learn how to calculate both the Heat of Rejection HR, (cooling), and Heat of Extraction HE, (heating). Your sixth grade math teacher, old lady Gillacuddy, will be proud as you put our math skills to work!
AHR EXPO 2014
I will be roaming around the EXPO aisles so if you see me please stop and say hi…I’m the old, fat, hippy looking guy…actually, here in NY that describes a lot of us!
HVACR Workforce Development Foundation
The HVACR Workforce Development Foundation is dedicated to leading an industry effort to develop and promote educational projects, programs and partnerships to attract committed and skilled employees to a career in HVACR.
- To raise the awareness of the HVACR industry and the importance it plays in daily lives.
- Create interest in the HVACR industry as an attractive and profitable career choice.
- To enhance the quality and quantity of available workforce for the HVACR industry.
As an HVACR industry ‘trainer’, I applaud the efforts of the foundation and I support their goals, as their goals are the same as mine…to raise the general perception of our industry and attract young, talented men and women to our workforce.
I have posted a video about the foundation at my website, Click here…the video about the foundation is the first one you will come to.
I encourage you to use the foundation’s website as a resource. You can visit them at http://www.careersinhvacr.org
The site is a clearinghouse for information about HVACR training programs throughout North America, scholarship programs and job postings. The foundation is the HVACR industry at its best…we recognize how good the industry has been to us and our families and we want to share that with the next generation…not only to insure their success, but to ensure the success of this wonderful industry for generations to come.
New videos posted on the website:
Besides the video I mentioned above, there are a couple more new videos posted since the last newsletter. ..be sure to check’em out!
Geothermal in Canada…’the times they are a changin’:
I received this very interesting article from my good friend, Hans Gautschi of HRC Services, about regulations imposed on geothermal drilling in Ontario…and new Canadian national standards which may have an effect on the industry as well. You can read the article here.
Do flat plate thermal solar collectors hold snow?
I haven’t done a thermal solar class in a while but when I was a player in that market a few years back, I remember an ongoing debate about flat plate versus evacuated tube collectors was ‘which will hold snow and which will not hold snow’?
Many of you know that I have a Sunnovations® Thermal Solar System (TSS) installed at my home that produces most of the domestic hot water for our home year round. I took some pictures of the collectors after a recent snow storm and I have posted them on my website…you can see them here. You will see definitive evidence that flat plate collectors do indeed hold snow.
The flat plate ‘community’ would insist that their preferred collector would not hold snow and that the evacuated tube collector would. My position at the time was that since the tube collector was just that…a series of tubes with space in between each tube, the tubes stood less chance of holding snow because the snow would simply fall through the spacing of the tubes whereas the flat plate had no defense against snow. I think the pictures prove my point.
I believe the myth about flat plate collectors and snow came from the fact that a flat plate collector will indeed be hot to the touch when in direct sun light but an evacuated tube’s surface will be at ambient temperature. This is all true but the problem with this argument as it relates to snow is that the sun is not shining during a snow storm and thus the surface of the flat plate collector will too be close to ambient temperature and as a result…hold snow.
Bottom line is snow is a temporary hindrance to flat plate solar collectors…the good news…in a day or two of sunshine all is right again!