Transthermal

Toyesi has been designing heat pumps in Australia since 1989. The business started up not just to build heaters, but to work with companies in saving and managing energy losses. Creating the Transthermal Energy Management solutions part of our business.

Peter Savtchenko (Des.Appl.Eng.Ref.Hvac.) our lead Engineer and Director, had a background in Thermal Dynamics and Water Dynamics when he started the business.  Using his vast knowledge of how water works, and how to manage the thermal energy transfer through thermal dynamics enabled him to design and build a heat pump that right from the beginning was more efficient than many of the players in the market at that time.

Custom building these systems over the last 30 years has given Peter a lot of Tacit Knowledge about heat pumps performance, their weaknesses and strengths. He has also seen a lot of change in the industry with a massive decline in the local manufacture of systems and a huge increase in the low priced imported systems.

Price-wise Australian Manufacturers cannot compete with the budget prices of these imported products, however, the quality of Toyesi systems still remains at the Premium End of the scale, and is unmatched still for quality and long life-cycle solutions. With systems still in operation 10, 15 and 20 years or more, Toyesi Heat Pumps continually stack up against budget systems for value for money.

Part of this success is the continued efforts of Peter and his development team, in tweaking, testing, and modifying our systems to maintain the highest levels of performance, efficiency and reliability.

So what is this Transthermal Section, and how can we assist you.

We have put together 7 methods for saving energy, and reducing running costs associated with pool & aquatic heating. We can’t help you with all of it, but we hope that the information goes a long way in helping.

There are two forms of heat loss from an Aquatic Environment whether it be a swimming pool, aquaculture tank, hydroponics set up or Greenhouse. Sensible and latent heat loss. These losses come from both the water body itself and the building the project is housed in.

Sensible heat loss is that loss due to a temperature difference, such as the temperature difference across the building envelope or the temperature difference between the make-up ventilation air and the exhaust air.

Latent heat loss is due to evaporation from the water’s surface and subsequently exhausting this moisture out of the building or expending energy to dehumidify the air. Almost all the heat loss from the water itself is due to evaporation from the surface.

Sensible heat losses can be reduced by adjusting the indoor air temperature, insulating the building and using heat exchangers.

 latent heat loss can be reduced by adjusting temperatures and humidity, using a pool or Tank covers during unoccupied hours, and installing a heat pump dehumidifier. Other measures include: installing pipework and adjusting the hours of operation of the circulation pump.

• Option 1 – Adjust Temperature
• Option 2 – Pool Blankets
• Option 3 – Install a Heat Pump
• Option 4 – Heat Pump Installation Considerations
• Option 5 – PCVER System including Dehumidification
• Option 6 – PAS for Environmental Control
• Option 7 – Install the Smart Transthermal Solution.

As a no capital cost step, investigate adjusting the water temperature, indoor air temperature and indoor relative humidity. The simple act of dropping 1 degree can save a lot of power and will reduce running costs.

We often see huge savings when quoting on the running costs at 27C or 28C rather than heating the pool to 30C.

High humidity levels will reduce evaporation as well as having room temperature close to that of the water body. It is possible to reduce evaporation from a pool surface to a low level or even zero by this strategy.

When humidity is high you can end up with a foggy indoor environment, water dripping off the roof and windows and this may lead to mould and rotting.

To remedy high humidity people often open windows, ventilate or dehumidify the space. However, remember any of these methods will reduce the humidity but will also increase evaporation and directly lead to increased running costs in pool heating. So great thought needs to be done prior to engaging such remedies.  See further down for Transthermal energy management ideas that can address and remedy humidity.

Be careful, however, not to go out of recommended ranges for temperatures and relative humidity. A compromise must be found between energy efficiency, swimmer or staff comfort, and building maintenance through humidity control.

Usually the most cost-effective energy conservation measure – other than adjusting air and water conditions – for both indoor and outdoor aquatic projects is to cover the water.

A cover eliminates up to 95% of evaporation from the water body depending on the cover used. As evaporation makes up 60% to 70% of your heat loss, you can see that a cover alone can save a good 50% of your energy losses, let alone the water savings benefit as well.

Many covers are designed to not only trap radiant energy inside the water body but let solar energy in, and trap that as well. So, make sure you use the right cover for your aquatic project.

As newer cleverly designed pool covers can even increase the water temperature by up to 8^oC during the day for outdoor aquatic projects, saving you even more on heating costs.

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Heat pump pool heaters are more efficient than electric resistance heating, and gas heating and can offer you significant energy savings, reduced greenhouse gas emissions as well as running cost savings.

A Toyesi heat pump can save you 40% to 70% of the heating running cost when compared to a gas heating system, and even up to 80% when compared to a direct electric element heating method.

The efficiency of a heat pump, know as Coefficient of Performance or COP, is a guide many heat pump providers use to demonstrate the efficiency of their system. It is a ratio of the energy used in kW verses the energy output of the system in kW. As a guide an electric heating element uses 1kW of energy to produce ~ 1kW of heating, giving a COP of 1.

Due to the efficient way heat pumps work, COP ratings of 4 to 6 are common. However, care must be taken when reviewing COP ratings, as many heat pumps are rated at their most efficient conditions. This being 27^oC water temperature and 27^oC plus ambient temperature, where there is no real work to be done.  Always consider the COP of the unit you are considering at the peak demand point, usually in the middle of Winter for a heating project where the most work is required.

Changing water temperature requirements as well as changes in ambient conditions will change the operating COP of a heat pump. The following graph will help demonstrate this point. It is based on 27^oC water temperature with varying ambient conditions for a Toyesi TET 600 SSD system.

You will notice that at a very wintery temperature of 6^oC, the TET 600 heat pump’s capacity is around 18 kW and a COP of around 4. However, as the weather improves to 19^oC its capacity has climbed to around 26 kW and a COP of nearly 6 is achieved. If you then move into Summer at an ambient of 35^oC the unit is now overperforming at 30 kW and a COP over 8.  We normally state this as a 26 kW System.

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Heat pumps draw heat energy from the ambient air, by drawing air through a heat exchange coil with the use of a fan. This fan then discharges, the now cooler, air away from the unit. Because of this need for air movement, around 95% of all heat pumps, on sale today, are designed for outdoor placement with their fans either on the front or top.

Front-mounted fan systems efficiently push this cooler air away from the heat pump, however many top mount fan systems have inherent air discharge considerations when placing them.

To prolong the life of any outdoor system, care must be taken to install the heat pumps, as best as possible, out of the direct elements and under a shelter, but this then can cause other issues especially for top-mounted fan systems. See above airflow issue.

Outdoor systems also suffer from direct exposure to the elements. Front-mounted systems can be easily protected from rain and direct sunlight by placing them under a cover. The same is not the case for top-mounted units, as you cannot risk trapping the discharged air. To help to increase the longevity of a heat pump you can consider the placement of the heat pump indoors. A shed or plant room is ideal.

Placing an outdoor designed heat pump indoors is a critical error many people make. This is since like mentioned above, heat pumps need access to airflow both into and out of the space.

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All heated water bodies give off heat energy through radiant heat and through latent heat through evaporation. This heat laden air in an indoor situation will be trapped within the space. The space will then heat up to the temperature of the water and increase in humidity levels until the air is saturated.

Maintaining a room temperature close to the water temperature may reduce radiant heat loss, but the air will still suck up water vapour till it is saturated.

The windows, walls and ceiling of the building will begin to sweat especially if the outside temperatures are lower than that inside. Water or condensation will occur, and you will notice this on windows or just simply dripping off the roof.

Dehumidifiers are the most common system purchased to remedy this situation. Yet another purchase, and system to run. Or the air is simply vented out, losing all that lost heat energy to the atmosphere.

In fact, this system was the original system with Transthermal energy management in mind. The older brother so to speak.

PCVER – Passive Cooling, Ventilation, Dehumidification, Ventilation & Energy Recovery System.

PCVER Advantages:

• Transthermal Energy Management
• Improved heat pump Efficiency through waste energy recovery.
• Improved heat pump Efficiency by drawing from a constant temperature body of air.
• Not as readily affected by outside air temperatures as an outdoor heat pump set-up.
• Creates a stabilised COP environment on par or better than any Geothermal system.
• Captures the lost heat energy before it is vented out of the room and puts it back in the water where it belongs.
• Actively draws air through the room assisting space ventilation.
• Cooler, dryer air can be returned to the room for space conditioning and dehumidification.
• Reduces capital expenditure by reducing the need for air-conditioners and dehumidifiers.
• Reduces running costs, by removing the requirements of additional equipment, and by running constantly at potential optimal efficiencies.

Toyesi’s system is an ideal solution for commercial Aquatic Projects, Indoor Pools and swim schools

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We came across many aquatic heating projects, wash bays and wet areas that had a problem with rot, mildew and mould build-up. To combat this, we saw a vast array of venting (wasted energy) and especially air-conditioning systems being used. The Air-conditioners were being used to control space temperature with the hope of managing the humidity and lost heat energy of the aquatic tanks.

However, the air-conditioners were being eaten alive by the moisture or humidity in the air passing past their circuits boards, fans, rusting, shorting out and even the mildew building up inside and more.

Constant downtime and repair bills or replacement units.

Toyesi developed the Transthermal energy management “PAS” system to combat these issues by using our advanced reverse cycle technology to offer true ambient temperature control by controlling a set dead-band setting. The system puts all the critical components outside the room preventing most of the issues.

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Our PCVER is designed for heating applications and uses waste energy to boost the heat pump’s efficiency and returns dryer cooled air for space temp managing but does not assist cooling applications.

Our PAS system helps manage a dead band temperature range to control space temp but does not increase heat pump efficiency.

One System to manage all the heating and cooling requirements

• Tank or Pool Temperature Control – Heating, Cooling or heater-chiller dead band control.
• Room Temperature Control – Heating, Cooling or heater-chiller dead band control.
• Ventilation Control – Passive and Active ventilation
• Reduced Humidity – Can return dryer air.
• Reduced Running Costs – One system instead of multiple systems.
• Increased Efficiency – Draws on latent waste room heat energy
• Energy Capture and Reuse – Uses waste energy to heat and or chill
• Greener footprint – Less wasted Energy
• Optional UV Return Air Sterilisation Kit – To minimise legionnaire and other airborne pathogens

That’s Transthermal Energy Management

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