Daikin develops new responses to environmental legislation
There are a lot of Daikin VRV air-conditioning systems out there using R22 which looked to have a short-term future with the phasing out of virgin R22. Now the company has come up with an upgrade strategy.
Environmental legislation in the European is both far reaching and forward looking. The phase-out of virgin R22 for service and maintenance work is imminent, with huge implications for the air-conditioning market. The Energy-using Products Directive continues to take shape, with small air-conditioning systems expected to fall within its scope during the next 18 months. In the longer term the EU’s 20-20-20 vision sets a target of 20% less use of primary energy, 20% lower CO2 emissions and 20% use of renewable energy by the year 2020.
Whatever else may or may not be happening in the rest of the world, air-conditioning companies wanting to operate in the European market are presented with challenges to respond to and opportunities.
Recent developments by Daikin Europe, which come to the market next year, address the issues of R22 in VRV air-conditioning systems, and the energy efficiency of air-conditioning systems up to 12 kW of cooling.
The phase-out of virgin R22 from 1 January 2010 in the European Union will present users of the huge legacy of Daikin VRV air-conditioning systems that use R22 (in other words, more than about eight years old) with potential difficulties in sourcing reclaimed and recycled R22 for maintenance.
In anticipation of this problem Daikin has been developing an approach that enables existing systems to be converted to R410A by replacing outdoor units, but retaining existing pipework and indoor units — so long as these indoor units date from 1996 or later. Existing VRV installations using R407C can also be converted.
Being able to retain existing pipework and indoor units and replace only the outdoor units and refrigerant clearly has a major impact on cost and disruption compared with total system replacement. BS boxes will also need replacing in heat-recovery installations.
The concept behind VRV-Q is that the refrigerant pipework is automatically cleaned, impurities retained within the new outdoor units and the correct amount of R410A automatically charged into the installation. These processes take about an hour, and it is possible to ensure a clean piping network even when a compressor breakdown has previously occurred.
The pipework needs cleaning because R22 works on mineral oil and R410A on synthetic oil. If mineral oil and synthetic oil are mixed in a system, acid is formed, which will corrode expansion valves, clog capillaries and could even cause compressor breakdown.
Another problem solved by VRV-Q is the different operating pressures of R22 and R410A. An R22 system works at 28 bar, compared with 40 bar for R410A. Daikin has addressed this problem by reducing the operating pressure for its new R410A equipment to enable it to work at lower pressures so that existing R22 pipework can be used. The trick is a sub cool circuit to enable high efficiency to be achieved even with the lower pressures.
A general concern about ‘drop-in’ refrigerants is a loss of cooling capacity — which is certainly not a problem with VRV-Q. Daikin’s figures indicate that an EER of 2.37 for a 10 hp system will be boosted to 3.89 with a VRV-Q system. Similarly a heating COP of 3.0 for a 10 hp R22 system will be boosted to 4.0 with a VRV-Q system.
Another way of looking at the improved efficiency is that more cooling can be achieved without changing the refrigerant piping. For example, it is possible to install a 16 hp replacement VRV on the refrigerant piping of a 10 hp R22 system.
Readers have a little time to start planning before VRV-Q becomes available in February 2010.
Daikin also has a response to the section of the European Directive for Energy Using Products covering air-conditioning systems with cooling capacities less than 12 kW. While the legislation is yet to be finalised and voted on, it is clear that the performance requirements of such systems will be based on seasonal efficiency, not efficiency at peak load. The legislation is expected to come into force sometime during 2011 or the first half of 2012.
Daikin’s response is the integration of eco-design principles into a new Sky Air series of split air-conditioners. Called Seasonal Inverter, it is said to be the first in the market optimised for seasonal efficiency and will reach the market in April 2010.
To put the concept into perspective, the nominal efficiency of reverse-cycle air-conditioning systems is measured at two sets of temperatures, one for heating and one for cooling. Cooling performance is measured at 35°C dry bulb outdoors and 27°C dry bulb indoors. Heating performance is measured at 7°C dry bulb outdoors and 20°C dry bulb indoors — temperatures that seldom occur. Another issue is who actually designs systems for those outdoor temperatures.
An important shortcoming of nominal performance at such conditions is that benefits of inverter control are not visible. Inverter control of compressors improves efficiency at part load compared with full load — and systems spend many more hours at part load than at full load.
The improved performance of Seasonal Inverter has been designed in from the ground up, and the seasonal efficiencies in real-life situations are truly impressive. If the current Super Inverter Sky Air range is given a seasonal efficiency of 100%, the nominal efficiency of the non-inverter Sky Air comes in at just 50% and the Seasonal Inverter at 120%.
The line-up of the Seasonal Inverter range will include outdoor units with cooling capacities from 7 to 14 kW using R410A. It may be possible to use existing R22 piping to refurbish existing systems, but outdoor and indoor units will need replacing.
The air-conditioning industry has a long history of responding positively to environmental concerns, international agreements and legislation. It all started with the Montreal Protocol on Substances that Deplete the Ozone Layer coming into force on 1 January 1989. The response of the air-conditioning industry has generally exceeded legislation, with new equipment becoming ever-more energy efficient. And the latest Daikin developments continue that tradition.
