Batteries included
Integrating renewable energy with high-performance battery technology will be a game-changer for buildings — believes Tim Mitchell of Klima-Therm.
Battery technology has come a long way in recent years. The main driver has been the relentless demand for ever-faster charge times and higher capacities in ever smaller spaces for use in mobile digital devices.
This has spawned a new generation of high-capacity, compact batteries based on lithium-ion technology that out-perform conventional lead-acid batteries in almost every way.
As production volumes have increased, the high initial costs have become affordable enough for the technology to be applied in areas as diverse as home appliances, such as battery-powered vacuum cleaners, and the main-stream automotive industry.
The recent announcement by pioneer Tesla, which it is developing an attractively priced all-battery-powered mid-range saloon car, was met with an overwhelming volume of pre-production orders — outstripping even the carmaker’s own most optimistic forecasts for demand.
The characteristics of new battery technology that make it such a potential game changer in the automotive industry (packing an unprecedentedly large amount of energy into an increasingly compact space and lightweight structure at an affordable cost) lend themselves to application in the building-services industry.
Indeed, in this age of potential brown-outs and demand-side response (DSR), it opens up a potentially transformational range of new and exciting possibilities for powering and controlling HVACR plant, which the industry is only just beginning to consider.
The key, I believe, is to take a ‘total energy approach’, which combines and integrates advanced battery technology with multiple renewable energy sources and mains power, to optimise plant performance and efficiency to reduce running costs and environmental impact and realise buildings that are more comfortable and sustainable.
Some fleet-of-foot pioneers are already working on practical application. Italian company Geoclima, for example, has developed what it calls the Teslamiser, a new power-supply management system initially designed for use with chillers based on Turbocor variable-speed compressors with magnetic bearings.
Although designed primarily for use with Turbocor because of its superior part-load performance, there is no reason in principle why the approach cannot be used with any chiller or HVAC system.
At its heart is a compact power pack based on the latest lithium polymer batteries, with a converter that controls charge and discharge of power to the chiller. The Teslamiser module can be mounted as an integral part of the chiller or installed remotely in a suitable location and then connected to the unit.
Under the control of an intelligent power-management system, Teslamiser automatically optimises energy flows into, within and out of the system. This includes managing the respective power inputs from the mains electrical supply and renewable sources, such as photovoltaic (PV) panels and wind energy, according to pre-set criteria.
This enables the system to harness the preferred energy source at any given time to power the chiller, with the battery pack providing the buffer. The power-source selection could be based upon the lowest cost, lowest carbon, perhaps even the most profitable, with some energy providers now paying customers to consume energy at certain times. For example, chiller batteries could be charged at night when tariffs are lowest or the greenest electricity is available; the accumulated charge would then be used during the day, avoiding peak electricity costs.
This approach delivers significant savings in itself, given the 15 to 20% reduction in night-time energy costs. However, there are further savings to be made through limiting peak power demand on a site, using the batteries to augment mains supply and renewable inputs to keep peak power within a predetermined limit.
This approach, known as peak lopping or demand side-response, is likely to become increasingly attractive for two reasons. First, the closure of older, more polluting power stations to comply with European carbon-reduction and clean-air targets is putting pressure on the availability of power at peak times. Second, the continuing roll-out of so-called smart metering will see costs for peak power being driven higher — and very much more than costs for off-peak power.
An essential aspect of the Teslamiser approach is the close integration of the chiller, battery pack, renewable-energy inputs and mains supply. Geoclima has particular expertise in software design and control engineering. Its custom algorithms are designed to make the most of (first) free energy from renewable or even profitable sources, (second) low-cost energy from the batteries and (finally) to manage the mix of mains supply, battery augmentation and renewable inputs to deliver the optimum chiller performance for the lowest possible cost.
A further advantage of the system is that it can operate as an uninterruptible power supply (UPS), maintaining plant operation in the event of a power cut for long enough to restore normal operating conditions. In critical applications, such as operating theatres and data centres, this is not just a nice-to-have but a ‘must-have’ capability.
With this new approach, UPS comes as standard rather than an expensive add-on, providing a high level of resilience that for many installations may previously have been out of reach.
Looking ahead, there are exciting possibilities for extending the capabilities of technologies such as Teslamiser to include intelligent recovery of energy directly from the chiller to charge the batteries — watch this space. This would create a genuine total-energy system that optimises power from all sources (mains, renewable and self-generated sources) for even greater efficiency and savings.
When one considers that the Turbomiser chiller in its basic form can be as much as 50% more efficient than conventional chiller technology, with K-Turbo machines being around 15% more efficient again, the addition of a Teslamiser-like power and control system with renewable inputs pushes the energy-performance envelope yet again to deliver unprecedented efficiencies.
We believe that in future all HVAC systems will be designed and built according to these principles, as total energy systems.
From thermodynamic, economic and environmental perspectives, it is the only rational way to go.
Tim Mitchell is sales director of Klima-Therm.
