Power Generating RTU

Every time I do research on a new HVAC technology I get excited, but at the same time I worry about the future of a refrigeration technician.  The bulk of my 4 years of schooling at SAIT was learning about refrigerant pressures, temperatures, condensers, evaporators and compressors. This new technology by the company BeCool could put guys like me out of work, especially ones that live in the southern hemisphere with high humidity and warm winters.

The new BeCool RTU doesn’t need refrigerant a condenser or an evaporator. It doesn’t need a compressor to move refrigerant or oil to operate. What it does have are three heat exchangers. HMX heat exchangers are cross-flow plate type exchangers. The first one is used to dehumidify the air, second one is an indirect evaporative cooler for cooling the dry air and the third one which is a natural gas regenerator that produces electricity.

The RTU draws process air into the first heat exchanger. The first exchanger dehumidifies the air using a high concentration of a salt solution, liquid desiccant . The desiccant dehumidifies the air by absorbing the water out of the air.  This absorption process creates heat that is added to the entering air. This hot dry air now requires cooling.  Water and outdoor air are passed over the HMX heat exchanger to cool the air. The water, outdoor air and  process air are not mixed. The process air is now warm and dry but needs further cooling. The process air enters an HMX evaporative cooler. Water is added once again to the evaporative cooler to cool the warm dry air. The continual flow of strong desiccant solution and a water source are the keys to this system. To keep the strong desiccant regenerating, a natural gas fuel cell regenerator is required. This fuel cell enables desiccant regeneration and creates electricity from the burning of the natural gas. The only two by-products are heat and water which are reused.

If you have a cheap source for natural gas, live in a warm humid climate, need power generated, then this technology when it hits the market in 2017 might be worth looking into.

 

 

 

HFO’s, Where’s Mulder and Scully when you need them?

As mysterious as the X files and UFO’s has been the information regarding the new generation of refrigerants known as HFO’s. The chemical name is hydrofluoroolefins and they are possibly the replacement for HFC’s. When I first heard of a new refrigerant, I immediately assumed it was designed as a safer refrigerant with low GWP (Global warming potential) and low ODP (Ozone depletion potential). Each article I read confuses me more as too the validity of the manufacture’s claims. The company Chemours manufacture’s the new HFO-1234yf refrigerant. Chemours is a chemical manufacturer that is part of the larger DuPont company.

Chemours claims that HFO-1234yf is 99.7% better than R-134a Refrigerant for its GWP. Since most vehicles manufactured in the United States and Canada currently use R-134a, this would be a significant improvement. The company claims that this product is not only better for its GWP potential for cars, it also improves upon the vehicles fuel efficiencies. The air conditioning system is lighter and more efficient so it will save you on fuel that would be needed on a heavier system such as CO2. Chemours

DuPont is the same company that invented Freon and were heavy investors in General Motors in its early infancy. Chemours refrigerant manufacturing division is now involved in both the refrigerant and automobile industries with HFO-1234yf. An article I recently read online that was written by a natural refrigerant manufacturer, Engas has a different viewpoint on HFO’s versus Natural refrigerants.  In it they reference the group Greenpeace and what they think about the new refrigerant. Greenpeace states that the refrigerant is not an improvement over the previous HFC refrigerants in automobiles. They claim the new refrigerant is nothing more than an HFC with a different more polished name. They claim that the risk of human safety should be of concern to all of us. The new refrigerant if leaks has been known to start an engine fire which produces hydrogen fluoride and carbonyl halides which are toxic and potentially lethal.

Fox Mulder and Scully might be able to solve this mystery but for now let’s hope that this isn’t another cover up.

 

Ductwork of the future?

When you think you’ve seen it all, along comes a product that could change an industry. The new product is called Gatorduct, and it’s completely manufactured from a type of cardboard called Tri-Wall. This cardboard is coated with a special Gatorskin which is fire retardant, moisture resistant and water repellent. The cardboard surface can be coloured and have graphics printed on it. The product is 80% lighter than sheet-metal, ships flat and is easy to assembly with nothing more than a jigsaw to cut it. The biggest selling feature will obviously be the lower cost for the contractor in ease of install and product cost. The product is 100% recyclable and currently made from 21.5% recycled material. The company manufactures in the U.K but is currently seeking UL approval in North America. Once the product is approved, the next step will be looking for someone to distribute it.

RTU Hybrid

Everywhere you look people are talking about hybrid cars, hybrid classrooms, hybrid diets and now a hybrid roof top unit or RTU. A company called Ice Energys have developed a hybrid cooling unit that works with a standard RTU. The RTU works as a standard cooling unit during non peak electrical periods of the day and the “Ice Bear” unit works with it during the peak electrical periods of the day. The RTU unit has an extra cooling coil added to it for the “Ice Bear”. At night the “Ice Bear” compressor starts and freezes the unit much like a giant ice cube tray. When the ice section is frozen solid, the compressor turns off. In the afternoon during peak electricity periods, a pump turns on inside the “Ice Bear” and the compressor in the RTU unit turns off. The pump moves cold refrigerant over to the extra cooling coil inside the RTU and provides cooling until the ice is completely depleted from the “Ice Bear”. At this point in time, the RTU compressor will start again if cooling is still required. Watch this YouTube video, Thermal energy storage to see the unit in operation.

While this isn’t a new idea, it certainly is a new product. I worked on a similar system on a high rise in downtown Calgary. The three chillers in the building would only run once the tanks of frozen ice had been depleted. At night, one or two chillers would run until the tanks were frozen and then shut off. In the morning the building automation system would have a cooling demand call and would start the  building pumps. The pumps would circulate water through the tanks cooling the water off to be delivered to cooling fan coils. When a certain percentage of ice was depleted from the tanks, one of the chillers would start, when a second set percentage of ice was depleted a second chiller would start and the same for the third chiller.

This is a fantastic idea but is unlikely to gain any traction in Alberta unless energy companies start charging different electricity rates for different times of the day. If we switch to the way other provinces providers charge for Time-Of-Use, such as hydro one in Ontario currently does, this could be an affordable option.