Summary:
To describe principles, concepts and implementation of the efficient utilities management systems in house and building. Main items presented in this chapter are:
- What means the efficient energy management in house and buildings
- Structure and elements of a energy management system
- Labelling of household goods and it’s advantages
- How work a Domo control system, details about the hardware and software implementation
- Metering systems used in house (electrical energy and thermal energy)
- Tele-metering systems; Automatic Meter Reading systems (AMR), principles, elements, and structure
- Lighting systems, switchers use for the commutation of electrical circuits
- Generation of electrical power in house or buildings, especially the Renewable Energy Sources (RES)
- Interfaces use to interconnect the efficient energy management elements together
1. What means " efficient energy management " in house ?
1.1. Definition
People consume in their houses different kind of natural resources like: water, gas and energy. In order to optimize the consumption, reduce the exploitation costs and increase the “comfort”, modern houses include digital processing system that implement different strategies in order to reach the goals above mentioned.
Not only the active, but also the passive measures are important in the global balance of energy. To enlarge house isolation layers, the amount of tools and household systems would be an example of passive measures.
A lot of initiatives are developed around the world. In Germany, for example the Deutscher Städtetag, Arbeitskreis Energieeinsparung (the German association of medium and big cities, working group energy conservation) has prepared energy guidelines for municipal administrations. The guidelines cover:
- Architecture
- Constructive heat protection
- Heating systems
- Ventilation and air conditioning
- Sanitary systems
- Lighting and other electrical systems
- Monitoring and control systems
The Life Cycle Cost (LCC) represents an important indicator that must be taken into account when a decision is made, but often, it is difficult to evaluate the cost of a particular implementation (see PROST part 2 – POLICIES AND TOOLS FOR ENERGY EFFICIENCY IN THE PUBLIC SECTOR).
The “efficient energy management” alludes especially to the electrical energy consumption management, but it involves also many other elements such as: scheduling the consumption adapted to the house needs and the programmed tasks, smoothing of the electric power curve and increasing the house comfort. The other forms of energy, like thermal energy, water and gas are not ignored either.
By modeling all the energetic resources it is possible to obtain an optimal usage of them. In figure 3.1 is illustrated one of possible optimization models:
Figure 3.1 Impacts of Energy Efficiency Programs On Energy Markets, by: Walter Gerardi, from McLennan Magasanik Associates, April 2004
The model takes into account the three main elements: the estimations related to the energy demands, coming from the consumer’s side, the electricity and gas capacity to cover the demands, coming from producer side, and the technologies that could be used to reach with minimum costs these needs of energy.
These are also associated with the impact on environment and economy resulted from the simulation. A very important factor is also the gas emissions (CO2 especially) generated by the production of energy and also degree with that are affected the energy resources for the future.
Latest goal in the optimal management of energy resources is represented by the sustainability of energy production, that means to reach a maximum efficient production and consumption of energy, to protect the environment and to obtain the social acceptance of the energy production methods employed (see figure 3.2). Safeguarding of the power resources becomes more and more a security problem for the majority of states of the world.
Figure 3.2 Triangle that represent the sustainability concept. To harmonize three requirements: efficiency, security and environment in the production and consumption of energy
1.2. Considerations about the energy efficient management systems
The energy management system comprises two aspects:
- The first is related to the self-power management system included into modern devices placed in house, such as: microwave ovens, refrigerators, HVAC systems.
- The second is related to the embedded controllers or PCs, which are used as supervisors of the house control.
An illustration of the main consumers in the house is given in figure 3.3.
Figure 3.4 Cost of energy bill for different household products. ”Others” include: ovens, microwave ovens, stove and other small appliance in house (source: http://www.energystar.gov)
Building management systems (BMS) and energy management systems (EMS) can turn on or turn off systems or selected equipment, based on time-of-day schedules or on variable parameters such as temperature.
These systems may be connected to other building systems such as fire alarm, security/surveillance, or access control. They can also coordinate other critical systems such as the elevator control and other utility management systems, like gas or water.
EMS and BMS systems are versatile and sophisticated controllers for a small building, a
large office or college campuses. With current technology and sophisticated software, the temperature, pressure, humidity, voltage, current, switch or relay status of many points throughout a facility can be monitored. These BMS/EMS systems can be programmed either to provide room comfort in the most economical way or to perform some energy management strategies, such as thermal comfort settings.
Applications employing energy management strategies have produced significant electrical energy savings thus making possible the return-of-investment (ROI) in three to four years.
When the facility is served under an utility time-managed rate schedule, these systems can be set to turn off major equipment or motors during peak hours.
The BMS/EMS can be used not only as a saving energy tool but also to cut off peak demands, in order to save energy. These systems can also generate a variety of utilities and energy consumption reports or analyses.
Animation 1 Which are the elements of house management system ?
The list bellow presents some examples of measures that have been tacked in order to increase efficiency in energy consumption:
Concerning refrigerators and freezers:
- Increasing the thermal isolation of refrigerators and freezers;
- Introduction of special fans for implementing air movement into these goods;
- Introduction of automatic defrosting systems into refrigerators and freezers, in order to increase the cooling process efficiency;
- Better design of temperature control (regulator) inside the refrigerator or freezer.
- Introduction of two compressors on the same system; this would provide better conditions for refrigeration and freeze processes.
Concerning microwave ovens:
- Better design of wave deflectors in order to obtain a better and uniform food exposure to microwave beams, thus increasing the heating efficiency.
- Introduction of multiple beam power intensity levels in order to better meet the practical needs.
Concerning washing machines:
- Modification of washing cycles and reduction of the water temperature.
- Introduction of new washing methods, e.g. “bubble machines” system.
- Adaptation of the washing cycle to tissue types and materials using “fuzzy logic circuits” for control. Fuzzy circuits allow choices between zero and one, and between true and false, using the whole scale of “grey levels” and not only the “black and white values”. These factors control the bubbles amount, the turbulence of the machine, and even the wobble of the machine.
- Implementing the Active Balance Control, ABC, to reduce noise and disturbances during spinning. With the ABC system noise and vibrations are reduced up to 50%. The machine increases the speed by small steps and goes up to full spin speed only when the laundry is evenly distributed and the drum is in complete balance.
Concerning dishwasher machines:
- Reduction of the water volume used in the washing process
- Improving the water distribution in the washing space filled with dishes
Concerning air conditioning systems:
- Introduction of mixed mode ventilation, which combines two different installations: one is the AC system that can supplement the cool /warm air in the house and another is a ventilation system that consumes only 20% of a classic AC system. At the same time, house comfort is increased. A mixed-mode building combines natural ventilation with mechanical ventilation and cooling and often incorporates sophisticated controls that allow the building to alternate between these two modes during different times of the day or season. This would maximize comfort while avoiding the significant energy use and the operating costs of year-round air conditioning.
- Zoning HVAC system, which means to define different zones inside the house and to use numerous thermostats, a well designed pine network for control and temperature regulation. A special feature of a thermostat could be the “warm” or/and “cool” anticipation. This means to be able to evaluate in advance the temperature variation profile in order to prevent the over heating or extreme cooling.
- Addition of a condensation cut-off to the radiant cooling systems that avoids the cases in which the radiant cooling surface temperature is so low that generates condensation.
Addition of new algorithms to the electric chillers so that to calculate heat recovery and to simulate a double bundled condenser.