Traditional and current electrical design practices for Voltage Drop overlook best practices relevant for digital age facilities such as data centers, robotic manufacturing complexes, and more. It is time to re-think current practice to capture extreme savings in both energy use (at least 7%) and electrical equipment (over-specification of equipment -- too much expensive copper).
The approach for this new age: optimize the utilization of the circuit's capacity to deliver the maximum amount of energy and reduce energy wasted through heat dissipation without adding more circuits and conductors.
What is Voltage Drop?
"Voltage Drop is the decrease of electric potential [Volt] along the path of a current [Ampere] flowing in an electrical circuit. Voltage drops in the internal resistance of the source, across conductors, across contacts, and across connectors are undesirable because some of the energy supplied is dissipated." https://en.wikipedia.org/wiki/Voltage_drop
In a power distribution system that supplies power to branch circuits for lighting and appliances, the National Electrical Code (NEC) provides guidance in an Informational Note that the maximum voltage drop of 3% for branch circuit conductors, and 5% for feeder and branch circuit conductors together, provides a "reasonable efficiency of operation for general use circuits."
This guidance fails to address the increasing complexity of digital age facilities.
Traditional and Current Electrical Design Practice
Traditional and current electrical design methods to minimize Voltage Drop are:
1. Increasing the number or size of conductors,
2. Reducing the load current on the circuit,
3. Decreasing conductor length, and
4. Decreasing conductor temperature.
Increasing the number or size of conductors
Traditional and Current Electrical Design Practice: By specifying parallel or oversized conductors, resistance per unit length is lowered below the NEC's requirements. This method decreases the Voltage Drop and increases energy efficiency while exceeding the NEC's minimum requirements for conductor sizes.
This practice for power distribution system design in data centers generally increases conductor sizes for phase, neutral, and ground conductors. Then, it goes even further adding an additional "parallel conductor" at the branch circuit to reduce the load by splitting it up.
Ongoing Issue: So using traditional and current electrical design practices, an additional conductor is added to the electrical design significantly increasing the cost of the equipment (expensive copper) in the facility. While the Voltage Drop is reduced, equipment costs are unnecessarily increased.
Reducing the load current on the circuit
Traditional and Current Electrical Design Practice: Current practice also deals with the Voltage Drop in digital age buildings by limiting the amount of equipment connected to a single circuit. This limits the load current on the circuit and also reduces the Voltage Drop.
Ongoing Issue: This limitation results in additional circuits being required...again, resulting in a significant increase in the cost of equipment (expensive copper) in the facility. While the Voltage Drop is reduced, equipment costs are unnecessarily increased.
Decrease Conductor Length
Traditional and Current Electrical Design Practice: Decreasing the conductor length, moves the source of electric energy closer to the load resulting in a reduction in resistance and the Voltage Drop. It requires the placement of expensive panel boards closer to the load.
Ongoing Issue: Again, this solution results in additional panel boards, feeders, and conductors at a significant increase in the cost of equipment (expensive copper) in the facility. While the Voltage Drop is reduced, equipment costs are unnecessarily increased.
Adjust Conductor Temperature
Traditional and Current Electrical Design Practice: Adjusting the temperature decreases the ampacity of the conductor requiring additional circuits.
Ongoing Issue: This limitation also results in additional circuits being required at a significant increase in the cost of equipment (expensive copper) in the facility. While the Voltage Drop is reduced, equipment costs are unnecessarily increased. Also, the more circuits in the system, the higher the energy costs as more electric energy is dissipated.
What's the problem?
With the world's increasing use and dependence on data, continuously expanding with streaming video, internet connected devices, and artificial intelligence, the demand for electric energy is expected to double every four years. And the expense of powering a data center is likewise out of control. According to Wikipedia, "the cost of power for the data center is expected to exceed the cost of the original capital investment." Wikipedia Data Center
Efforts to reduce energy consumption at data centers have been heroic - from improving server power draw to reducing energy use in storage, network, and infrastructure. But this "low hanging fruit" has not been enough to satisfy the insatiable need of data centers for electric energy.
More needs to be done to control Voltage Drop in these digital age facilities as extreme savings are easily possible for both energy use and equipment costs. It is time to "re-think" traditional and current electrical design practices.
A new approach: actual reduction of the number of conductors and circuits
Like traditional and current electrical design practice, PowerCalc increases conductor sizes to reduce heat generation due to friction during the transmission / distribution of electricity inside the facility. It meets the minimum requirements of the NEC, but meeting the NEC's minimum requirements does not mean that a design minimizes electric energy losses and maximizes electric energy savings.
PowerCalc meets the initial threshold of the NEC's design requirements by increasing conductor sizes just like in traditional and current electrical design practice. But then, PowerCalc goes a step further: it also decreases the actual number of conductors and circuits. This reduction is accomplished by bundling more loads on these larger conductors.
Traditional and current electrical design practice increases conductor sizes without adding more electrical loads to these conductors. In contrast, PowerCalc uses the larger conductor size to maximize the load for said conductor by bundling. This "new" approach makes additional conductors and circuits unnecessary for reductions in electric equipment (expensive CU) and electric energy costs for extreme savings.
How does PowerCalc design to reduce the number of conductors and circuits?
PowerCalc's energy savings module (ERASE(tm)) focuses on saving energy and optimizing the design of the power distribution system before a facility is even built or renovated by focusing on how electricity is transmitted / distributed inside the facility.
ERASE's approach is unique: it focuses on the conductor / wires that transmit electricity...the single largest link between the generation and end-use consumption of electricity. It saves 7%+ of energy use by optimizing the design of the power distribution system inside the facility.
And for the data center, ERASE eliminates the need to add unnecessary conductors or circuits to reduce the Voltage Drop. This re-thinking results in extreme savings in both electric energy use and equipment costs.
Unlike other electrical design software, PowerCalc's patented process designs from the bottom-up, i.e. from the circuit to the service entrance / power grid. For the first time, the ability to calculate and specify the exacting detail of conductor sizes is easily possible due to PowerCalc's automation of the traditional and current electrical design practice.
Listed on US DOE's Building Energy Software Tools Directory
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