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Innovative Climate-Control System to Extend Range of Electric Vehicles and Improve Comfort

Periodic Reporting for period 2 - XERIC (Innovative Climate-Control System to Extend Range of Electric Vehicles and Improve Comfort)

Reporting period: 2016-12-01 to 2018-05-31

The limited capacity of electric batteries combined with the substantial amount of energy needed to run auxiliary equipment dramatically affects the range capability of electric vehicles. For instance, the climate control system in Summer conditions can absorb up to 60% of the available energy.
XERIC’s aim was to develop an energy-friendly climate-control system for electric vehicles capable to reduce by more than 50% the energy used for passenger comfort all over the year.
Currently air is dehumidified and cooled by using climate control systems based on the traditional vapour compression cycle, which cools air below its dew point.
Alternatively, solid or liquid desiccants are used as an energy efficient way to dehumidify air without cooling it below its dew point, which allows to control temperature and humidity independently. However, current desiccant systems cannot be used in vehicles.

In XERIC we have worked to exploit technologically the properties of aqueous solutions of desiccants housed in a novel three-fluids-combined-membrane-contactor (3F-CMC) that simultaneously works with air, desiccant solution, and refrigerant. The idea is to develop a hybrid system in which air can be dehumidified without the need to be cooled below its dew-point; therefore, the overall system efficiency increases.

The objective was to develop an industrially viable hybrid climate control system for electric vehicles able to guarantee comfort to passengers and to reduce by more than 50% the energy used.

The following activities have been developed:
• integrate a liquid desiccant cycle housed in a 3F-CMC with a vapour compression cycle;
• devise a new customized membrane to optimize the performance of the 3F-CMC;
• devise an electronic control system to improve efficiency of climate control system’s compressor;
• manufacture a small-scale prototype capable of processing 100 m3/h of external air (i.e. about 30% of the typical air flow rate through the passengers’ cabin);
• evaluate the environmental impact of the climate control system as part of life cycle analysis and life cycle cost analysis assessments.

XERIC’s partners are:
3. UNIVERSITY OF GENOA (UNIGE), IT - acting as 3rd partner of TICASS
The exploitable results are:
A small-scale prototype of an energy saving climate control system (CCS) has been designed, manufactured and tested.
The “small-scale prototype” is a prototype capable of processing about 67 m3/h of the renewal air flow rate needed (i.e. about 33 % of the typical renewal air flow rate to the passenger cabin).
The current climate control system is capable to:
1. reduce more than 50% the energy used all over the year for passenger comfort (i.e. air heating, cooling and dehumidifying) compared to existing systems that rely on electric direct heating in wintertime;
2. reduce up to 32.9 % the energy used for air cooling/dehumidifying in extreme summer conditions (i.e. external air at T=30 °C and RH=60 %) to guarantee comfort in the passenger cabin (i.e. T≈25 °C and RH≈50 %);
3. The 3F-CMC can be customized to accommodate different air flow rates. The present size of the CCS is still too large to fit in the space available in most EVs currently on the market and miniaturization of the system is foreseen after-project with the help of OEMs working in the EV market;
4. since the most of the CCS components are standard ones and widely used, the only components that can undergo some life-related issues are the 3F-CMCs.
5. the system has been tested under the following external air temperatures ranges: in heating mode, from -10 to 10 °C, but there is no technical reason for the heat pump not to work in the [-20 °C, +15 °C] temperature range; in cooling/dehumidification mode, from 20 °C to 45 °C;
6. the air side pressure drop is smaller than 100 Pa (before the passenger cabin air filter); i.e. fans currently installed in EVs can be used;
LCA indicates that in Germany the average reduction in environmental burden is around 40 % in four impact categories: Climate change, Terrestrial Acidification, Photochemical Oxidant Formation and Freshwater Eutrophication.
In Italy, it ranges between 41% and 29%.

In the framework of XERIC the results have been proven at TRL6. It is worth noticing that in Annex 1 of the Grant Agreement we had planned to reach results validated at TRL4.

Some partners are setting up a new project to industrially exploit the results and take them from TRL6 to TRL9 in collaboration with a large international OEM active in the EV market.
Also work is in progress to exploit the results by academia in the framework of the Erasmus Mundus Master on Membrane Engineering.
The results reached leads us to believe that XERIC technology can be exploited either to extend the range of EV and/or to decrease the battery size.
This latter fact is extremely important for EV manufacturers because the cost of batteries is the largest cost in an EV as reported in figure.
Moreover, according to recent surveys the market of EV is going to grow faster than expected and reach more than 150.000.000 vehicles by 2030; this fact encourages industrial developments to accommodate these two needs: range and battery cost. In fact, in the last few years both governments and privates are continuously and aggressively working to create infrastructure and laws to encourage the use of electric cars. Some partners of XERIC consortium are exploring the possibility to scale up the resuts at industrial level and target the market of E-bus and E-boats, where available space (to install the new system) is larger and battery cost is higher.

XERIC doubtless is contributing to improving the innovation capacity of industrial partners (GVS, AIN, and FRIGOMAR) which have benefitted from the collaboration with UDE, VITO, TICASS/UNIGE, ITWM, and EMH. All partners have shared knowledge in a cross-organizational and trans-disciplinary manner both to carry on the anticipated research plan and to solve unexpected problems which indeed have arose. To the contrary research organization driven by the ambition of industrial partners to take to market the new products, have focussed more and more on an industry led approach to accommodate specific market needs; i.e. scale up requirements, product cost and price, quality, replicability, and time-to-market.

All the above considerations encourage our consortium in investing resources and time in this market sector; i.e. climate control systems for EVs.
technological steps within XERIC
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XERIC in a nutshell