Environmentally friendly, cost saving hot water solutions

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Mitsubishi Heavy Industries Air-Conditioners Australia has released an innovative sanitary hot water solution that addresses two of the biggest issues facing manufacturers, sustainability and energy costs.

Given its use in everything from plant wash downs to pasteurisation, access to a reliable hot water supply is a must-have for many food and beverage manufacturers. The problem is, the traditional means of producing readily available water has been both expensive and environmentally unfriendly.

In response to this, Mitsubishi Heavy Industries Air-Conditioners Australia (MHIAA) has released the Q-ton – a highly efficient, air-to-water hot water solution which utilises CO2 gas as a refrigerant. According to the company, the unit uses a safe, natural and environmentally responsible refrigerant. This has natural accruing properties that give the Q-ton advantages over conventional refrigerant heat pumps.

MHIAA describes it as a breakthrough in terms of both sustainability and reduced running costs.

Suitable for use by food processors, distillers and other manufacturers, the unit features a coil of cold refrigerant that absorbs heat from the outside air, as well as the world’s first two-stage compressor (combining state-of-the-art rotary and scroll technology).

A hot water solution with high efficiency rates and low carbon emissions, the Q-ton delivers outstanding performance as a solution based product. The product recovers heat energy from the air and can perform in extremely cold temperatures (down to -25°C).

“Q-ton supplies hot water from 60°C to 90°C at 100 per cent capacity at an outdoor temperature down to -7°C and will continue to produce hot water down to -25°C,” Trent Miller, Air-to-Water Manager for Mitsubishi Heavy Industries Air-Conditioners Australia, told Food & Beverage Industry News.

Essentially, the pump forces air through an evaporator that contains CO2. The heat in the air is then passed through the evaporator before being absorbed by the CO2. The refrigerant is circulated in the system via the compressor causing its temperature to rise as it passes through the compressor and a heat exchanger. This heat is then transferred to the passing water before being delivered into the storage tank.

The Q-ton produces hot water at off peak electricity times and stores it in a tank for daytime use, offering a large cost saving for operators and is considered a direct replacement for boiler systems as it controls the water supply and storage temperature as well as the output capacity.

According to Miller, it offers a number of important advantages compared to the conventional alternatives.

“When you use a normal hot water solution, the conventional refrigerant can’t achieve the high temperatures of hot water. Furthermore the conventional alternatives cannot perform in lower temperatures and require the use of an electric element in heating,” he said.

Miller explained that, before the arrival of the Q-ton, there was no way for such units to manage highly compressed gasses. “The CO2 in the Q-ton has a resting temperature of about 5500 kPa while a conventional refrigerant may only have a couple of hundred. As soon as the compressor starts up, we will be getting pressures of up to 12000 kPa which is a lot of energy,” he said.

Heat pumps are rated by their Coefficient of Performance (COP), which is the ratio of the energy output over the energy input. The higher the COP ratio, the more efficient the unit. The Q-ton boasts an industry-leading COP of 4.3. According to Miller, depending on the application, that figure can be even higher.

“In a distillery in Tasmania, the Q-ton was installed instead of their originally planned electric line heater because of the projected energy savings and proven COP that the Q-ton gives. The 4.3 COP is actually a conservative estimate that is based on the standards in Japan where the ambient temperature of the water is much lower,” he said.

“In warmer climates like say Cairns, depending on the incoming water’s ambient temperature, it could require a lot less energy to heat and the COP could be a 5 or 6.”

Improved sustainability

The innovative hot water solution also offers significant environmental benefits.

“Because we are not using conventional refrigerants, we are eliminating the emission of hydrocarbons which can damage the atmosphere. This is the main reason why we should be using natural refrigerants,” said Miller. The Q-ton has been rated as having Ozone Depletion Potential (ODP) of zero.
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Miller explained that, as a by-product of the refrigeration process, the unit simultaneously produces cool air. Manufacturers can take further advantage by using both to their benefit.

“If you had an abattoir you could mount the units in the cool rooms. Each unit has 20kW of cooled air. So if you had five units there’s 100kW of cold air coming off the top of it,” he said.

For example, you can produce hot water to perform plant wash downs while, at the same time, using the cooled air to refrigerate your cool areas and keep product fresh.

Safety and predictive maintenance

Miller pointed out that safety is another key selling point for the system. “The refrigerant charge is only 8.5kPa per unit which is roughly what’s in a fire extinguisher. It’s a very small charge. Safety wise, it gives businesses a lot of control over their hot water,” he said.

For example, where businesses want to reduce the chances of Legionella they need to heat water to 90°C.

“Rather than keeping everything heated to 90 degrees all the time, they can elevate the cycle, run it to that heat, and then come back down to something that’s safer to work with. Unlike a gas boiler it ramps up then ramps down. Normally people set it and forget it,” said Miller.

“We’ve got a touch screen remote or you can do it remotely through your computer and change the temperature to within 0.5 of a degree so that’s really going to change how people work with hot water.”

This remote monitoring capability, combined with inbuilt sensors within the unit, allows operators to oversee the operation of the unit system as well gather a lot of useful data such as the amount of hot water produced and energy used on a per day basis.

“With this information, customers can then have more visibility on how efficiently they are running their manufacturing processes in, let’s say, an abattoir or a dairy plant,” said Miller.

The fact they can use the data to deliver predictive maintenance programs is another reason the unit represents a step forward in heat pump technology and can help businesses looking to increase operation efficiency and improve their bottom lines.

While Miller conceded there is a competitor in this space, he pointed out that those are larger units than the Q-ton.

“We have a unit that can be modulated together. The versatility of our unit and our ability to increase the capacity size required for the job means that users have more control over the system. Other systems tend to have larger size units which do not allow for modulated flexibility within the product,” said Miller.

He explained that this, in combination with the company’s rich history in variable flow refrigerant technology (air-to-water) found in the VRF systems, gives the Q-ton system the edge in the market in providing a sanitary hot water solution to commercial spaces.

“With the Q-ton it’s not a split system, it’s all self-contained. You’ve got no one welding in the system. It’s all water in, and water out. That means we’ll get a lot longer run hours and a lot longer design life out of ours just because there’s no interaction with the refrigerant circuit from the tradesmen. It comes pre-set,” said Miller.