Energy Quote

The state's combination of abundant renewable resources, high fuel prices, limited geographic area, and recognized expertise in hydrogen technology R&D, makes it an ideal location to lead the state's transition to a renewable energy-to-hydrogen economy. By attracting considerable investments of capital and expertise to Hawaii, we will be investing wisely for our future needs.

Ted Liu

Smart Grid

Smart Grid attempts to predict and intelligently respond to the behaviour and actions of all electric power users connected by adding monitoring, analysis, control, and communication capabilities to the national electrical delivery system. It aims to maximize the throughput of the system while reducing the energy consumption. The Smart Grid will allow utilities to move electricity around the system as efficiency and economically as possible. It will also allow the homeowner and business to useelectricity as economically as possible.

With smart grid, it is possible to employ tactics for improved efficiency:

  •  smart meters,
  • dynamic pricing,
  • smart thermostats and smart appliances,
  • automated control of equipment,
  • real-time and next day energy information feedback to electricity users,
  • usage by appliance data, and
  • scheduling and control of loads such as electric vehicle chargers, home area networks (HANs), and others.

25 Aug 2011 20:14:07

Ground Source Heat Pump

A ground source heat pump (GSHP) or geothermal heat pump is a central heating and/or cooling system that moves heat to or from the ground. It uses the earth as a heat source for heating in the winter or a heat sink for cooling in the summer. Unlike an air-source heat pump, which transfers heat to or from the outside air, a ground source heat pump exchanges heat with the ground. This is much more energy-efficient because underground temperatures are more stable than air temperatures through the year.

Ground source heat pumps must have a heat exchanger in contact with the ground or groundwater to extract or dissipate heat. This component accounts for a third to a half of the total system cost. Several major design options are available for these, which are classified by fluid and layout. Direct exchange systems circulate refrigerant underground, closed loop systems use a mixture of anti-freeze and water, and open loop systems use natural groundwater.

8 Jun 2011 20:44:31

Radiant Cooling

A cooling system that relies on temperature-controlled surface (ceiling, wall or floor) to cool indoor temperatures by removing sensible heat through thermal radiation. Heat will flow from objects, occupants, equipment and lights in a space to a cooled surface as long as their temperatures are warmer than that of the cooled surface and they are within the line of sight of the cooled surface. The process of radiant exchange has a negligible effect on air temperature, but through the process of convection, the air temperature will be lowered when air comes in contact with the cooled surface.

The majority of radiant cooling systems are hydronic, cooling using circulating water running in pipes in thermal contact with the surface. Due to the high heat capacity and density of water, thermal energy can be transported in water in pipes by low power pumps, saving approximately 70 to 80% of fan power normally used in conventianal air-conditioners.

Typically the circulating water in hydronic radiant cooling (HRC) only needs to be 2-4°C below the desired indoor air temperature. Since the coolant can be maintained at a high temperature level, the use of heat pumps with high coefficient-of-performance values, cooling towers, night cooling, or some combination of these can reduce electric power requirements further.

7 Jun 2011 19:50:23

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