Energy Management - Part 2

STRATEGIES FOR SUSTAINABLE DEVELOPMENT

Responsible energy use is fundamental to sustainable development and a sustainable future. Energy management must balance justifiable energy demand with appropriate energy supply. The process couples energy awareness, energy conservation, and energy efficiency with the use of primary renewable energy resources.

Energy Awareness

To sustain its own wise use of energy, the sustainable development must demonstrate benefits rather than sacrifices to its users (which includes visitors and operators).
Functional requirements and user comfort are maintained while efficient lighting, ventilation, and appliances make prudent use of renewable energy resources. Energy production and efficient use are visible and interpreted components of the total sustainable development experience. The user enjoys learning about sustainable energy concepts and feels good about it. The demonstration of sustainable energy use offers an opportunity for changing perception, patterns, and value systems.

As an example, in areas where there is visitor lodging, energy awareness could be enhanced by in-room energy meters. The meters would let visitors know how much energy they have used much like exercise machine meters have workout analogs. Interpretation would encourage and reinforce economical energy use. Visitors who conserve energy could be rewarded with facility perks or a discounted bill. The meters should be simple, informative, and fun.

The comprehensive advantages of sustainable alternatives over conventional approaches can be communicated through comparison of the source and amount of energy required for a particular service, and the associated environmental and economic cost implications. By promoting less consumptive lifestyles and demonstrating more sustainable energy alternatives, the sustainable development can more effectively balance the demand and supply sides of energy management responsibilities.

Energy Conservation

At the beginning of the planning process, a determination must be made to avoid energy-intensive or unnecessary operations. Considerable energy can be conserved if access to, from, and within a development is planned around transportation systems, bicycle routes, and pedestrian walkways rather than perpetuating the use of personal automobiles.
Facility design can contribute to energy conservation in several ways. Through recycling existing facilities, building only the minimum to satisfy the functional requirements, and having facilities serve multiple functions, the embodied energy of new building materials and the energy of transporting and constructing them are minimized. In addition, considerable electrical and thermal energy can be saved through facility design that incorporates daylighting and the other passive energy-conserving strategies appropriate to the local climatic environment. Any food service associated with the development could also contribute to energy conservation by emphasizing fresh, locally available items that minimize the amount of energy required for transportation processing, freezing, and refrigeration.

In all cases, mechanical air-conditioning of facilities is energy-intensive, and in most cases, proper attention to the principles of site planning and building design can effectively eliminate its need. Awareness of the cooling sense of moving air and the connection to the natural resource can enhance the user comfort and the visitor experience without air-conditioning.

Fresh air is desired in a resource-related development. Breezes, the sound of birds or the surf, and the smell of flowers are fundamental to the perception of air. Wind chimes, used in traditional Japanese architecture, serve as a gentle reminder of a cool breeze. The sound of trickling water in a courtyard fountain can impart the perception of coolness. A ceiling fan spinning overhead can provide not only a sensory but also a psychological feeling of a cool breeze.
In visitor lodging, energy use can be minimized through "designed-in" restrictions or charges on consumption to visitors. Elimination of electrical outlets in individual lodging units would curtail the use of visitor appliances such as hair dryers and electric cooking utensils. Instead, electricity should be provided only at central locations such as bathhouses, and limited in individual units to fixed devices or appliances, such as lighting or a fan. Certain services such as laundry or showers or high wattage electrical outlets could be coin operated and timed because they are so energy intensive. The visitor could be informed of their energy use with a continuous display, and rewarded or charged depending on consumption.

Energy Efficiency

Efficient methods, devices, and appliances should be employed at the sustainable development to conserve energy. Almost all facets of the development and visitor services and amenities can profit from recent innovations in energy efficiency.

As an example, no bulb is cheaper to buy and more expensive to use than an incandescent bulb. Over 90% of the energy consumed by most incandescent lamps is released as heat. The substitution of one compact fluorescent bulb for an incandescent bulb will save a barrel of oil (money), keep about 2,000 pounds of carbon dioxide (global warming), and 20 pounds of sulfur oxides (acid rain) out of the atmosphere. For the owner, each $10 compact fluorescent bulb will save approximately $40 in energy cost over the life of the bulb. The 100-year-old incandescent bulb will soon go the way of the oil lamp.

Lighting. Natural lighting should be used wherever possible. The quality and ambiance of natural lighting are unsurpassed and it is free. Lighting design should be based on standards of reduced general lighting with task lighting and highlighting for specific functional considerations.

Where artificial light is needed, regular and compact fluorescent lighting should be used.
Fluorescents are greatly improved with color rendition comparable to incandescents and electronic ballasts to totally eliminate perceptible flicker. They use 75% less electricity. Average life is 10 times longer than incandescents, reducing maintenance and transportation costs. In most circumstances, the economic payback for new fluorescents is under two years. The environmental payback is immediate.

Sensors and Controls. Lighting, ventilation, and other devices or systems can be controlled with a variety of sensors that reduce electricity consumption significantly. A photocell can control day and night operation. Occupancy sensors (motion or ultrasonic) can operate lighting. The infrared sensor uses less energy to operate and is less sensitive to air movement but does not see around corners. An ultrasonic sensor can be used in a restroom and even detect movement around partitions. Other sensors are available that can control operation of a device by door opening, time of day, timer, noise level, and proximity.

Refrigeration. Efficiency of refrigeration mostly depends on insulation but also on the temperature of the condenser. High insulation levels and efficient compressors are available in only a few refrigerators and freezers. They will reduce energy consumption significantly, using only 20% of conventional units. Any site-constructed walk-in freezer should strive for similar efficiency through a combination of super insulation and heat exchange with relatively cooler reservoir. Open chest freezers should be avoided. Individual dwelling units could be supplied with an ice source efficiency cooler instead of a refrigerator, but these units should be well insulated.

Laundry Facilities. Energy-efficient conversion kits are available for standard electric washing machines, which reduce energy consumption by two-thirds by replacing the motor with an energy-efficient model. Clothes should be air-dried whenever possible.

Low Energy Transportation. Resource-related development should be laid out with an emphasis on pedestrians and a reduced dependency on fossil fuels. Walkways and hiking paths can encourage walking. The rental of bicycles and sailboats, rather than scooters and jet skis, and the coordination of efficient public transportation to the development can all serve to reinforce less consumptive lifestyles.

Load Management. Additional system efficiencies can be realized by controlling the duration, time, and timing of loads to increase the use of the supply system. This decreases peak demands. Control strategies will depend on characteristics of the energy supply system as well as loads. For example, water may be pumped to a storage tank in a gravity system during sunlight hours for a solar electric system, during off-peak hours for a small hydro system, or during generating periods for a wind system. Intelligent load management will increase the amount of energy delivered to perform useful tasks and decrease the size of the supply system.

Renewable Energy Resources

Once energy awareness, conservation, and efficiency measures have been employed, renewable energy sources should be investigated for providing the needed energy. Site conditions and available resources as well as energy demand will determine the sources to develop. Reliability and maintainability of conditions at the development are also important considerations. Energy systems should be decentralized, reliable, and locally maintainable. Spare parts should be stocked, and maintenance and operating expertise must be perpetuated through documentation, education, and training programs.

If a technology is chosen that does not meet these criteria, i.e., a new technology or a system for which no local expertise or experience exists, and if its operation is critical, then a standby system, such as a propane generator, should be considered. A long- term support and training agreement with the supplier is also necessary.

Specific examples of renewable energy resources and their characteristics, applicability, advantages, and disadvantages are described here.

Solar Technologies. A broad range of solar technologies exists - some are as simple as sun tempering a building by orientation and shading as discussed in the "Building Design" section. A clothesline is an example of simple solar technology that should be used in a sustainable development. Low technology systems are readily available to preheat water and dry foods. Medium temperature systems can provide refrigeration. Solar collectors with multiple units ensure reliability.

Low Temperature Thermal Systems. This class of systems is commercially available, and both installation and maintenance requirements are familiar to the electrical and plumbing trades.

• Swimming Pool Heaters. Swimming pool heaters are commonly manufactured of low-cost PVC or CPVC materials and are in the form of a simple piping loop with a circulator pump. Controls are simple and can even be omitted in most southern latitudes.
• Domestic Hot Water Heaters. Domestic hot water heaters are typically closed-loop systems used for providing potable hot water to household or commercial facilities. They come in a variety of shapes and sizes, but generally include a water-heater storage tank, either of the common household water heater type, or of a solar applications design that has an additional heat exchanger and superinsulation. The solar collectors are generally flat-plate designs that vary from manufacturer to manufacturer. These systems are simple to install, and maintenance is low. Payback varies with comparison to local rates, but is generally two to three years.
• Medium Temperature Thermal Systems. Air-conditioning or industrial-process water heating are typical applications of these systems. These systems are less common than low temperature systems, and installation requires an experienced contractor and several weeks of project time. Payback is extended when the application is for air-conditioning. Domestic hot water can be a by-product of the absorption unit, and will defray operating costs somewhat. The collectors themselves are cost-effective, and systems using them to pump water and other such uses are very cost-effective.
• Photovoltaic Systems. Ample sunlight, low maintenance, high reliability, and widespread support make photovoltaic systems and attractive option for remote energy generation. System design is flexible and easily expanded. A development can be energized by a single centralized large array and battery storage, or smaller autonomous systems serving local areas, even individual dwelling units. Although there may be cost advantages for a centralized system, there are reliability advantages for a number of small modular systems with interchangeable components. Electrical storage is by lead-acid deep-cycle batteries, similar to those used in golf carts. Although there are many variables a typical hotel room or studio apartment could be powered by batteries of 300 amp hours at 12 volts, including a four-day reserve. Typical battery total costs would be about $1 per amp-hour. This would include fans, lights, TV or stereo, an occasional high load such as a hair dryer or whirlpool bath, and a high-efficiency refrigerator. Peak loads such as cooking would be best handled by natural gas or propane. Direct current electricity is generated and stored. Reliable, efficient, high-capacity inverters that convert the stored energy to 120 volts AC for running conventional appliances are available.
• Hydroactive Systems. Small-scale hydroplants are generally comprised of Pelton wheel generators that operate from low-head, running streams of water. They are reliable and cost-effective, and can be serviced by competent mechanics with hydraulic and electrical skills. Storage batteries can be used to buffer peak electrical demands. Wave-action generators are comprised of hydraulic or pneumatic pumps that pressurize an accumulator to drive motor/generators. These systems can stand alone or be disguised by incorporating them into docks and other shore emplacements. They work well wherever there is small wave action, such as in harbors and marinas, or in seashore facilities. They are reliable and cost-effective, and maintenance is simple. Storage is designed into the system to meet electrical demands. They work best where demand is intermittent, such as for cycling pumps.
• Wind Systems. As with solar technology, the simplest use of the prevailing winds is incorporation into the architecture. Wind scoops, cross-ventilation, and passive thermal chimneys use air movement to keep buildings comfortable. Wind generators can be a good choice for remote applications and small power demands such as pumping water. Major maintenance should be performed by the dealer.
• Biogas Use. As a by-product of the anaerobic digestion of the solid waste stream (see "Waste Prevention" section), biogas offers the comprehensive benefits of waste and wastewater processing, methane production for cooking and refrigeration, and generation of organics for soil enhancement. Depending on the quantity of waste that is available, possibly all the energy needs within a sustainable development may be met through the use of biogas. Biogas might also be used in the production of ice at off-peak periods to sustain the marketability of local produce or the fishing industry. Biogas should be used to directly fuel gas refrigerators, stoves, absorption-chillers, and water heaters. A simple orifice change is required to adapt these appliances to the Btu (British thermal unit) value of the gas supply. This will typically be done by the manufacturer if specified. Gas-fired engine generators should be used if the energy balance indicates that sufficient energy is available for that purpose. Proven heavy duty propane generators will be more reliable and quieter than the diesel-converted models of some U.S. manufacturers. One warning in this process is to not buy used equipment unless it is fully researched and warranted and the parts readily available and the service available within one week.

ACTIONS FOR SUSTAINABLE DEVELOPMENT

With the ultimate goal of sustainability, the following actions summarize an approach to reduce energy consumption:

• Identify the availability, potential, and feasibility of primary renewable energy sources such as solar, wind, biogas, and geothermal to satisfy the justifiable energy needs of the development.
• Apply the best principles of siting and architectural design to reduce energy demands and to minimize the need for energy-consuming utilities (air-conditioning, water heaters, high-level artificial lighting).
• Make energy production and use a visible component of the sustainable development. Broaden visitor experiences by awareness of energy use issues and the use of efficient appliances, conservation methods, and renewable energy sources. Install energy meters to monitor and illustrate energy consumption.

Source: http://www.nps.gov/