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Sustainability > Key Activities 2014 > Spread of Net Zero Energy Buildings
Fiscal 2014 Key Activities

Environment: Spread of Net Zero Energy Buildings. Net Zero Energy Buildings Help Realize a Low-Carbon Society.

Why is it Important?

Increasing Worldwide Prevalence of Net Zero Energy Buildings (ZEBs)

With the increase in energy consumption of office buildings and other commercial facilities in recent years, the need for energy efficiency is growing. Net zero energy buildings, or ZEBs, are becoming increasingly prevalent in Japan and other developed countries as a major contribution to achieving a low-carbon society.

Like the name suggests, a net zero energy building is one that utilizes energy efficiency in its structure and facilities while also creating its own energy through renewable sources so that its net energy use becomes zero. Europe has set a target of having all new buildings be ZEBs by 2020 while the U.S. is aiming for 2030. Japan’s target is also for all new commercial buildings to be ZEBs by 2030, and this means there must be dramatic reductions in the energy consumption of air conditioning, a large chunk of a building’s electricity use.

Net Zero Energy Building

Net Zero Energy Building

Building Electricity Consumption

Building Electricity Consumption



Demonstration Tests Under Industry–Government–Academia Tie-Up

Daikin is working to raise the energy efficiency of VRV (multi-split type air conditioners for commercial buildings) and other air conditioning products, as well as propose optimal energy management based on the specific needs of regions around the world with the goal of realizing ZEBs.

In 2008, Daikin’s Environmental Technology Laboratory teamed up with a major architectural firm to calculate how much electricity consumption needed to be reduced to achieve a ZEB. It was found that air conditioning-related energy would have to be reduced by 60%. Toward achieving a ZEB, Daikin began developing VRV building air conditioners with dramatically greater annual operational efficiency, and in a project under New Energy and Industrial Technology Development Organization (NEDO), Daikin, the architectural firm, and Nagoya University carried out joint demonstration tests.



Combination with DESICA Air Conditioners Boosts Efficiency During Low-Load Times

During the development process, we discovered a technology that could cut air conditioning electricity consumption by 60%. The operational efficiency of conventional air conditioners drops drastically when there is a small difference between the outside temperature and the air conditioner’s set temperature, and this low-load period accounts for about 90% of annual operating time. We therefore focused our development efforts on improving efficiency during this low-load time.

To boost efficiency during low-load times, we developed a number of key technologies. For example, a new scroll compressor, which dramatically minimizes the leakage and loss during compression, and fully automatic energy-efficient refrigerant control, which determines necessary load on the go and controls compressor RPM as necessary.

Because optimal energy efficiency can be achieved by controlling temperature and humidity with separate equipment, we aimed to maintain room comfort while reducing energy consumption by controlling temperature with the VRV building air conditioner and humidity with the DESICA air conditioner (humidity adjuster).

Relation Between Load and Operating Time (for Office Buildings; Daikin figures)

Relation Between Load and Operating Time(for Office Buildings; Daikin figures)

The operational efficiency of conventional air conditioners drops drastically when there is a small difference between the outside temperature and the air conditioner’s set temperature. A study of annual usage conditions revealed that air conditioners operate under this small temperature difference about 90% of the time.

71% Electricity Reduction with New System

Using a new system incorporating these new technologies, including the ones which would take time to be put into practical use, we embarked on demonstration testing under a NEDO project. Test results show that electricity consumption can be reduced by 47% during cooling and 27% during heating over conventional systems. In addition, we conducted energy simulations of this system installed in a highly airtight, highly insulated building, and found that savings of 71% in annual electricity consumption could be achieved.

Some new technologies that could be put to immediate practical use were incorporated in our VRV X-Series multi-split type air conditioners for commercial buildings released in March 2015.

Four Features of the Verification System



Verify ZEB Effectiveness Through Demonstration Testing in Japan and Other Countries

The air conditioning system we developed will be incorporated with other systems such as heat storage and natural heat usage systems, and employed at our Technology and Innovation Center (to open in November 2015 inside Daikin’s Yodogawa Plant), where we plan to use it to test its effectiveness in reducing energy consumption in large buildings. To promote the spread of ZEBs overseas, it is necessary to test the effectiveness of systems in a range of environments differing in terms of factors like heat and humidity. In fiscal 2015, Daikin plans to conduct demonstration testing under a joint industry–government–academia tie-up in Singapore that will show air conditioning system performance in tropical climates.

Stakeholder's comment

Daikin Technology Holds Promise for Energy Saving in Humid Tropical Regions

In highly humid tropical regions such as Singapore, the use of conventional air-conditioning and mechanical ventilation systems leads to over-cooling and energy inefficiency. That’s why room air comfort and energy savings are more effectively achieved by controlling temperature and humidity separately.

To this end, Daikin and the Building and Construction Authority of Singapore, along with an alliance of three major universities called BEARS*, are testing Daikin’s DESICA in actual working environments to evaluate the effectiveness of this new technology in reducing energy consumption. The study results are expected to lead to the adoption of this green technology in tropical regions.

*BEARS (Berkeley Education Alliance for Research in Singapore): An educational research and development body of the University of California Berkeley that is working in collaboration with institutes such as Nanyang Technological University and the National University of Singapore

Dr. Tseng King Jet Associate Professor, Nanyang Technological University; program co-leader, BEARS SinBerBEST

Dr. Tseng King Jet Associate Professor, Nanyang Technological University; program co-leader, BEARS SinBerBEST


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