Our Heating and Cooling Technology
Applications scope
Heating and cooling technologies covers a very large spectrum of equipments. Depending on what the requirement is, different solutions can be proposed.
Our domain of expertise are heat pumps and chillers.
Heat Pump
A heat pump is a device which main purpose is to transfer the heat present in a thermal reservoir such as the environment at low temperature into a process that requires heating at higher temperature.
The heat is transported by a coolant from heat pump to the process.
The main use of heat pumps is comfort heating. However, heat pumps are more and more used in industry where heating is traditionnaly ensured by fossil fuel burner.
A chiller is the complete opposite of a heat pump. Its main purpose it to transfer heat at relatively low temperature from the process to a thermal resevoir such as the environment.
The heat is transported by a coolant from the process to the chiller.
Chillers are mainly used in industry for process cooling. They are also often used for comfort cooling where air-conditioning is centralised.
How does it work?
Though there are exotic heat pump and chiller technology that are under development, most heat pumps and chillers are using the MVC process to make a refrigeration cycle.
Indeed, in thermodynamics, the best refrigeration cycle is the Inverted Carnot Cycle. However, realizing such thermodynamic cycle is impossible.
In order to approach the Inverted Carnot Cycle, we exploit the thermodynamic phase rule that states that the quantity of variable that describes the thermodynamics state of a compound is linked to the number of phase in which it coexist.
For pure compound, this means that:
  • if it exists in only one phase (liquid, solid or gas), temperature and pressure can vary independently
  • if it exists in two phase (liquid-gas, liquid-solid, or solid-gas), temperature is linked to the pressure.
By exploiting evaporation and condensation, it is possible to follow rigorously two stage of the Inverted Carnot cycle: the isothermal expansion stage and the isothermal compression stage. To link these two stages, on one hand, we are using MVC process, and on the over hand, we are using simple expansion valve.
This refrigeration cycle works for nearly all existing fluid. However, depending on the fluid, there is intrinsic achievable efficiency.
The choice of the refrigerant is a compromise between different criteria such as its price, its volumetric capacity at the working pressure, its environmental impact and its hazardousness.
What's the problem with current technology?

Today's technology is harmful for the environment

Chillers and heat pumps intensively use fluorinated gases which are polluting gases.
Since the signature of the Montréal protocole in 1987, regulation has always evolved to constrain the use of fluorinated gases because of their environmental impact.
The first generation, CFCs, was responsible for the destruction of the Ozone Layer.
The second generation, HFCs, contributes greatly to global warming: 1kg of fluorinated gas has the same global warming potential (GWP) as 9.4 tons of CO2 during 20 years and 3.5 tons of CO2 during 100 years. HFCs represents one-third of industrial greenhouse gas rejection (energy excluded).
The third and newest generation, HFOs, is already critized because of safety issue and known environmental impact. They are flammable gases which raises safety concerns since, contrary to domestic gas, HFOs temperature can reach high temperature. They also degrade in the atmosphere into TFA, a very persistent pollutant, and tropospheric ozone, a pollutant that contribute to air toxicity.
All over the world, governments and institutions are trying to ban the use of high GWP fluorinated gas. Europe has already stated in a firm resolution its will to ban the use of such fluorinated gas. Asian countries are becoming more and more concerned by the problem of fluorinated gases. With environmental and safety issues raised for HFOs, it is only a matter of time before they are banned or strictly constrained.
Finally, even though HFOs are not yet constrained by environmental regulations, they are using fluorspar as raw material in their manufacturing process. However, Fluospar is a critical raw material. It is estimated that by 2050, the known fluorspar mines will be depleted.
Our technology

1/ Water as a refrigerant !

We are using the most natural refrigerant in the world : water! Every good thermodynamic specialist knows that water can be used as a refrigerant. They also know that using it is very tricky. But tricky doesn't mean impossible.
New technologies has made possible and economically sustainable a solution that was prejudiced too complex in the beginning of the refrigeration era. And not only water can be used as a refrigerant, it also has better efficiency than most fluorinated refrigerant. And its environmental neutrality makes it possible to optimize the thermodynamic cycle in such ways that, for the same operating conditions, we can expect efficiency 30% higher than for conventional solutions.

2/ Direct contact heat exchange

In traditional chillers and heat pumps, because refrigerants can be polluting and/or hazardous, the refrigeration cycle is always closed inside the machine in order to limit the quantity of refrigerant used.
To allow heat transfer from the process to the machine, a circuit of coolant is used. The coolant is circulated using a circulation pump. By doing so, in the case of a chiller, the cold coolant is transfered from the machine to the process. In the process, the coolant absorbs heat and so the coolant temperature rises. Then, the hot coolant returns to the machine and evacuate the heat to the refrigeration cycle by using a heat exchanger.
The heat pump works under the same principle but with an inverse way.
In both cases, the coolant used is usually water.

In our case, the coolant and the refrigerant is the same fluid: water. This is made possible because water is neither polluting nor hazardous. Moreover, water is affordable. So there is neither environmental, security nor economic constraints to use water in excess.
In such case, the heat exchanger that separate the refrigerant line and the coolant line is not required. By removing this heat exchanger, it is then possible to achieve higher energy efficiency since the heat exchanger is a source of inefficiency.

Traditional Process

Leviathan Dynamics Process

3/ A unique high speed centrifugal multi-stage refrigeration compressor

MVC process require evaporation. However, MVC process with water as the working fluid requires operation under deep vacuum to allow the evaporation at low temperature.
The problem with vapor under vacuum is that they are very light. In our process, water vapor is up to 100 times lighter than air. Since it is mass that vehiculate heat, we need to transfer a very high volume flow rate in order to obtain exploitable cooling power.
With existing compressor technologies, compared to a machine that works with fluorinated gases, we would require compressor 20 times bigger. To avoid this problem, we developped our own compressor.

Our benefits
Traditional solutions use fluorinated refrigerants which are obtained from complex chemical synthesis. These refrigerants are expensive.
Moreoever, because they are polluting and/or hazardous, they must be monitored and carefully handled. Hence, there are induced hidden costs for all maintenance operations.
Meanwhile, water is inexpensive and easily available. And since it is neither polluting nor hazardous, only simple monitoring system is required and maintenance operation are much more easier.
And since efficiency of our machines is higher, overall operation costs is much lower than traditionnal solutions.
In our operating condition, water allows an intrinsic gain of energy efficiency of 5% compared to R134A.
In addition, the use of our direct heat exchange process allows the reduction of energy consumption by 25% on the design operating condition.
Finally, in our design, it is much more easier to integrate free cooling since the condenser can be used as an air-water heat exchanger. Only one heat exchanger is required and no additional pressure drop is generated with our free cooling design.
Overall, for processes where cooling is required the whole year, a reduction of energy consumption up to 60% can be expected.
Unlike fluorinated gases which have great impact on the environment and are becoming scarce, water is abundant and not toxic neither to environment nor to humain. It is an inexpensive fluid that is largely used in industry: its use will never be banned and it will always be available.
Knowing this fact, we are designing much more sustainable machine to make them last much longer, with correct maintenance, than traditional machines.
End of life of our machines is also easier to handle since there is no depollution required.