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heat pumps

Global capacity for directly-used geothermal energy stands at more than 70,000 MWt. Over 70% of this capacity corresponds to the so-called geothermal heat pumps, with a total of 50,000 MWt, followed by spring resorts and spas (9,140 MWt) and domestic heating and DHW networks (7,556 MWt). More than 80 countries use geothermal energy directly in a range of applications (heating, spas, dehydration of vegetables, greenhouses, drying wood, heat pumps, etc.). The top five countries with the largest installed capacity for directly-used geothermals worldwide are: China, with 17,870 MWt; the US with 17,416 MWt; Sweden, with 5,600 MWt; Turkey, with 2,886 MWt; and Germany with 2,849 MWt (2014 figures).

However, only 23 countries use geothermal resources to generate electrical power. These countries have a total installed capacity of more than 13,000 MW, with Mexico ranked fourth with a total installed capacity of 1,081 MW. Although the capacity in effective operation is only 883 MW, as at December 2015, representing just under 2% of the country’s total electrical output, it is able to cover the electricity demand of some two million Mexican households.

In Mexico, the commercial generation of electricity from geothermal energy has been taking place since 1973. To date, this industry has been controlled by the Federal Electricity Commission (CFE), via its Department for Geothermoelectric Project Management (GPG) that currently operates the four existing operational geothermal fields in Mexico. Read more…

Article published in: FuturENERGY March 2016

Saudi Arabia as the greatest worldwide economies, has established a compulsory energy labelling system for electrical appliances, in order to reduce the energy consumption. These regulations apply as well to the air conditioning and heat pump appliances.

Saudi Arabia Standards Organization (SASO) and Saudi Energy Efficiency Center ( SEEC) procedures require that air conditioning and heat pump equipment complies with energy efficiency requirements according to standard SASO 2663 “Energy labelling and minium energy performance requirements for air-conditioners”, and tests according to SASO 2681 (split or windows type) or SASO 2682 (ducted type). SASO establishes as well that exporters/manufacturers will carry out their measurements in testing laboratories approved by SASO.

CEIS has been included in the authorized laboratories SASO database, increasing its accreditation scope with standards SASO 2663, SASO 2681 and SASO 2682. Thus, CEIS becomes the first European laboratory recognized by Saudi Arabia Authorities in the framework of energy labelling for air conditioning.

Since 26 September 2015, the Ecodesign ErP Directive has been of compulsory application for EU Member States as regards the design of Energy-related Products (ErP) and as from its entry into force only those products manufactured according to the ErP requirements can be sold with the EC label. Although this directive affects over 1,000 product categories, for those relating to HVAC and DHW production, it covers boilers, heat pumps, accumulators, cogeneration systems, combined products systems, establishing their minimum efficiency levels, the maximum levels of NOX emissions, the minimum insulation for accumulators and the maximum level of acoustic emissions for heat pumps.

Heating and combi boilers that have had to comply with the ecodesign requirements since September 2015 include those with outputs of up to 400 kW, for which the standard has defined a minimum energy efficiency level to be complied with. This means that the new ErP Directive will prevent the sale of less efficient heating and combi boilers that do not meet the minimum performance requirements indicated in the Directive. In practice, this means that the market will tend towards condensing boilers which are almost the only type that can achieve the minimum requirements established by the ErP.

Another substantial change introduced by the Ecodesign Directive is that performance for the boilers that until now has been defined on the basis of the LCV (Low Calorific Value) will now be defined based on the HCV (High Calorific Value).. Read more…

Gaspar Martín
ACV, Technical Director

Article published in: FuturENERGY January-February 2016

Understanding that each technology has a preferred way of operation (some of them prefer being fully charged frequently, others don’t etc.), and accepting that high performing technologies require a more “intelligent” battery management system (BMS) due to safety reasons, we decided more than 5 years ago to develop a proprietary but open universal interface to connect our inverters to different battery technologies.

The use of lead acid batteries was mandatory from the very beginning – available all over the world, comparably cost effective, no need for a specific BMS. We developed and from then, continuously improved our specific, configurable set of algorithms for the optimised operation of lead acid batteries, so at least the majority of today’s available lead acid batteries can be connected to an SMA inverter. In the last few years, we’ve been working closely together with battery manufacturers to define a set of parameters for their specific cells/batteries, allow a long service life and outstanding performance.

Upcoming technologies, starting with lithium as the new state of the art residential battery technology, require a matching BMS not only for diagnostics but also for safety reasons. These management systems set up a communication link with the inverter and define both the current limits and preferred set points within the operational range. The inverters will adapt these values into the operational strategy to match the demands of the application with the effective capability of battery, influenced by environmental values like temperature etc. Both communication protocol and safety requirements are publicly available, to allow battery manufacturers as well as system integrators to implement this link into the BMS feature set.

But compatibility is not only a question of the communication link. First of all, the voltage has to match – batteries are a combination of battery modules, consisting of battery cells, so the battery manager can chose a system voltage in a certain range. We discussed the system voltage in our last PV Tech Storage Guest Blog contribution, so we will not elaborate on this in detail. System integration has an impact on a variety of other functions, such as the awakening procedure after a system shutdown. Connecting power electronics to a battery means directly connecting the discharged capacitors of a DC link to a fully charged battery – typically causing significant inrush currents.

If you ever tried to mount a fully charged starter battery to your car, you might have an idea of this effect. If the inrush currents would put the “health” of the battery at hazard, a pre-charge strategy has to be implemented, either on the inverter or on the battery side.

One of the questions we’ve been frequently asked at SMA Solar Technology is how compatibility with the existing variety of batteries in the market can be put into practice.

Let’s start with some brief historical background. Batteries have always been one of the main focus topics in the SMA world. In the 1980s, the first off-grid systems supplying power to whole islands were commissioned. A battery inverter would act as the heart, charging and discharging a large-scale lead acid battery and controlling the operation as well as stability of the overall system. One important aspect was – and still is – to understand the battery’s needs under various operational conditions, and then find an algorithm to meet them while optimising the system’s performance.Waschmaschine

More than 20 years’ experience has qualified us to understand the influences of specific applications on the sizing and performance of the battery. As the development and diversity of battery technologies gained momentum, it became obvious that there is no “perfect” technology for any application and each conceivable requirement. As a system solution provider, it was more than obvious that it is mandatory to support a variety of technologies to meet the customer’s demand.

Which battery technology for which application?

About two or three years ago, it looked pretty much like the tasks appropriate to various different battery technologies had been set, plain and clear.

The upcoming technologies were divided into two basic categories: the right solution for high power solutions was Lithium, which was very expensive but allowed to provide enormous amounts of power in short time periods, while for high energy solutions, Sodium based technologies were chosen, promising the lowest costs for stored energy, but with some drawbacks in terms of dynamics.

Nickel based technologies looked like they might be reduced to niche applications – which still looks to be the case – and flow technologies promised to be a solution for long term energy storage. lead acid batteries, even while being flawed with the stigma of being a more or less “vintage” technology, were the right choice for cost-driven applications with basic requirements regarding cycle life and efficiency. Examples include like UPS (uninterruptible power supply, or back-up power), or for off-grid systems, where the installed capacity was merely influenced by the “survival time” after an emergency, typically the loss of generation. A battery designed to provide power for two or three days after no generation is available, will have to withstand daily cycling of less than 10% of its capacity while generation is available.

From a general perspective, all of this is true. The major game changer was the competitive situation on the market. Whereas sodium battery suppliers have not been facing strong competition, and actually, there are only three or four of them owning the IP to provide solutions, the lithium world has had to face the fight for the pole position in the e-mobility projects of large OEMs.

Resulting in huge investments into R&D as well as production capacity, lithium suppliers succeeded in bringing down the costs in a way that changes the game completely. Comparing current or recent tender results for large scale energy projects, lithium seems to beat sodium even if the costs per kWh are compared. And in residential markets, the first lithium battery systems provide a better pricing than lead acid systems, if the costs per “usable” kWh are taken into account – a result of the fact that lithium batteries allow lower depths of discharge without a reduction of the expected lifetime.

Comparing the figures on the German residential energy storage system (ESS) market, within two short years, from a small share of lithium installations that was not really challenging the leading position of lead acid battery based systems, has shifted, dominating this market with more than 80% of lithium installations today. Supporting both technologies was – and is – key to maintain a leading position in this market segment.

 

The use of heat pumps in geothermals is gaining ground in Europe’s residential sector as an alternative to traditional boilers. Geothermal sources are particularly suitable for heat pumps thanks to favourable thermal levels and constant temperatures throughout the year. Multi-purpose EXP systems with two-pipe installations are a development that benefit geothermal units and offer the most appropriate solution from an energy and easy installation viewpoint, at least for the residential sector. Air-to-water units have been on the market since the mid-1990s.

These are technologically advanced machines, only manufactured by a small group of companies and are currently available for geothermal systems, also in water-to-water mode. This configuration is even more interesting because it responds to a series of installation and operational problems that, as explained below, would otherwise be difficult to resolve.

The use of geothermal products in the residential sector primarily aims to reduce CO2 emissions into the atmosphere to a minimum in line with the Kyoto Protocol. Water-to-water heat pumps are thermal generators capable of emitting the least CO2 in its different operating modes, much less than condensing boilers or an air-to-water heat pump. Read more…

Guillermo Martínez
Product Manager, Cooling Machines Sedical, S.A.

Article published in: FuturENERGY June 2015

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