WO2000016055A1 - Cycling energy metering - Google Patents

Abstract

A method to continuously monitor closed-system energy sources of the cycling type, such as refrigeration compressors and furnaces, through temperature and time measurements alone. It will measure (a) average energy consumption of a closed system and (b) the efficiency of the associated energy sources. For this method to work successfully, the output of the energy source must exceed the heat load that must remain constant over the measuring interval.

Description

Cycling Energy Metering

Background - Field of Invention

This invention relates to a method to measure energy output of heating sources such as a furnace, or cooling sources such as a refrigeration compressor through measurement at regular intervals of closed system temperatures and elapsed time. These energy sources shall start and stop at regular intervals.

Background - Description of Prior Art

Heretofore there was no practical way of monitoring the efficiency of closed heating and cooling system installations. Given the nature of these processes, there was no simple way to track their performance, wear and tear.

This invention was developed as a result of an inquiry while marketing a previous and somewhat related invention, i.e., Cycling Compressor Performance Metering for which a U.S. Patent, No. 5811669 was obtained on September 22, 1998. It then became obvious that a need for a method for this type of application was required.

No background was uncovered. My previous patent operates on a similar cycling principle, but measures flow of ideal compressed gases instead.

Objects and Advantages

Accordingly, several objects and advantages of this invention are:

• Non invasive measurement and verification of the thermal output of cycling heating or cooling sources.

Metering of energy flowing in and out of a closed-system.

Tracking wear and tear of cycling energy sources by measuring gradual changes in the output. • Continuous supervision of heating and cooling sources.

• Eliminates uncertainties about energy sources output and consumption rates.

Further objectives and advantages will become apparent from a consideration of the ensuing description and accompanying drawings.

Brief Description of the Drawings

Fig. 1 shows a computational sequence, i.e., a flow chart, in which the process variable measurements and energy calculations take place.

Fig. 2 shows how the temperature changes over time in a system controlled by the ambient temperature of a medium and by the starting and stopping of an energy source. It is referred to as "System Temperature Cycle."

Fig. 3 shows a typical temperature control system installation diagram, with two energy sources, a void referred to as "closed-system", temperature transducers, a general purpose data processor referred to as CEM, a display and an optional alarm interface.

Definitions

Closed-system: a volume, a closed-space or a solid object to or from which no mass is being added or removed, respectively.

CEM: a general purposed data processor of known type, capable of:

1. performing additions, subtractions, multiplication and division;

2. accepting analog type signal inputs from temperature transducers;

3. accepting digital type inputs from energy sources start and stop operation contacts;

4. measuring time intervals;

5. executing a sequence of calculations

6. storing calculations, constants and states in a memory area

7. displaying and conveying results; Summary

A method to continuously monitor cycling closed-system energy sources.

Preferred Embodiment

FIG. 1 - Computational Sequence (software)

A Cycling Energy Meter is a computational sequence, FIG.l, executed by a data processor of known type, that calculates the exchange of energy in and out of a closed-system from temperatures measurements, thereby allowing supervision of a controlled energy source while in service. All necessary external variables are provided from of system temperature sensors and energy source start and stop signals.

Step 1, Start - Initialize Registers, is the first step required when turning a data processor on.

Step 2, Wait for Dissipation Stage, indicates that the sequence should wait for the system temperature to move in its 'natural' direction. This could be up or down, depending on the type of energy source. If the energy source is of the cooling type, the temperature will move up after the source shuts down, and vice-versa.

Step 3, Energy Source stops. Dissipation Stage begins and indicates a signal is received confirming this event.

Step 4, Read System Temperatures, TO. Set Time Register to 0, indicates the commencement of the temperatures rate-of-change measurement.

Step 5 - Wait for Pump up Stage (Pumping starts when Energy Source starts) indicates the interval that comprehends the measurements of step 4.

Step 6 - Energy Source starts - Pump up Stage begins, indicates that a signal was received confirming this event.

Step 7, Read System Temperatures TL, and elapsed time, tL, records the elapsed time and new pressure. Step 8, Calculate the Energy loss EL. Store EL in a register. Display EL, indicates that the system energy loss can now be calculated and displayed.

Step 9, Wait for Dissipation Stage, indicates the time interval while the energy source is engaged.

Step 10, Energy Source stops. Dissipation Stage begins, reflects that a signal was received confirming this event.

Step 11, Read System Temperatures TU, and elapsed time (tϋ-tL), records the duration of the pump up stage and the new temperatures.

Step 12, Calculate the Energy added EA. Store EA in a register. Display

Energy added by Source, EA+EL, indicates that the energy source output can now be calculated and displayed.

In short, the temperature rate-of-change will be clocked at regular intervals and multiplied by the system mass and specific heat. This calculation provides the resultant amount of heat entering or leaving the system, depending if the temperature is increasing or decreasing, respectively.

FIG. 3 - Typical elements, (Hardware)

A typical Cycling Energy Meter will consist of the following elements: a general data processor of known type able of (a) performing additions, subtractions, multiplication and division; (b) accepting analog type inputs from temperature transducers; (c) accepting digital type inputs from an energy source(s) start and stop signals; (d) measuring time intervals; (e) storing calculations, constants and states in a memory designated area; (f) displaying and conveying results.

Preferred Embodiment - Operation (FIG. 2)

Measuring the temperature change while the energy source is turned off, allows calculation of the amount of energy the system dissipates during the measurement interval. It is therefore necessary to calculate the amount of energy dissipated by the system first. This can only be done while the energy source is off. Once an energy source starts, the temperature rate-of-change will be proportional to the balance of heat entering and leaving the closed-system. This is known as the first law of thermodynamics.

Mass x SpecificHeat x TemperatureChange Energy rate-of-change = Power =

Timelnterval (of TemperatureChange)

See Fig. 3. Once the energy source starts pumping up and, if the source's output exceeds the amount of energy dissipated by the closed-system, the temperature will change in the opposite direction. While the energy source is pumping up and the resultant stored energy is increasing, the temperature rate-of-change is measured and the excess amount of energy pumped into the closed-system is calculated.

By adding the calculated excess amount of energy pumped into the system to the previously calculated amount of energy dissipated, the total amount of energy pumped by the energy source can be calculated, provided the dissipated energy rate remained constant during the whole cycle.

Other Embodiments

Stand-alone CEM - Description

As a stand-alone unit, a Cycling Energy Meter consists of a digital electronic device capable of:

a) accepting and processing signals (1) from temperature transducers and (2) from optional start and stop signals from the operation of energy sources b) a clock, to measure elapsed time between temperature readings c) executing a sequence of calculations d) storing data, as needed to provide repeatable physical data e) a means to display the results.

Stand-alone CEM - Operation

A stand alone Cycling Energy Meter will operate as shown in FIG.l CEM as part of a system control center - Description

Cycling Energy Metering lends itself readily to be absorbed as part of centralized or distributed control systems, as found in major industrial plants, power, chemical and commercial Heating Ventilating and Air Conditioning plants.

The required temperature signals and optional energy source start and stop signals may already be in the system. In this case, only the necessary program sequence, algorithms and means of display shall be added.

CEM as part of a system control center - Operation

The Cycling Energy Metering operation as part of a system control center shall be as shown in FIG. 1

Conclusions, Ramifications and Scope

Accordingly, it can be seen that Cycling Energy Metering can adopt many embodiments, e.g., as a stand-alone digital electronic instrument with a suitable display, or connected to and part of a major control system.

Although the previous examples contain specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Various other embodiments and ramifications are possible within its scope.

The scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.

Claims

Claims: What is claimed is:

1. A method for calculating one or more of the following:

a) energy dissipated from a closed-system b) energy pumped into a closed-system c) closed-system energy source efficiency d) closed-system energy source wear-and-tear e) closed-system energy source load-factor f) closed-system energy source load-change

while operating a general purpose data processor capable of: keeping track of elapsed time intervals, storing in registers reference and calculated values, accepting system temperatures as variable signal inputs, executing the mathematical operations of: addition, subtraction, multiplication and division; capable of:

i) measuring a closed-system temperature rate-of-change, while energy sources are off-line and thereby calculating the energy dissipated from a closed-system (a);

ii) measuring a closed-system temperature rate-of-change, while energy sources are on-line and thereby calculating the balance of energies pumped into and dissipated from a closed-system;

iii) calculating energy pumped into a closed-system, by adding the energy dissipated from a closed-system (i) to the balance of energies pumped into and dissipated from the closed-system (ii);

iv) calculating a closed-system energy sources efficiency (c), by dividing the energy pumped into a closed-system (iii) over the energy sources original factory output;

v) calculating a closed-system energy source wear-and-tear (d) by calculating the inverse of the closed-system energy source efficiency (c);

vi) calculating a closed-system energy source load-factor (e) by dividing the energy dissipated from the closed-system (i) over the energy pumped into the closed-system (iii) vii) calculating a closed-system energy source load-change (f), by dividing the actual energy dissipated from a closed-system(i) over a previously calculated (i)-value used as a reference.

2. A data processing device of known type capable of executing the process sequence and formulae on a closed system, accepting said system temperatures as variable signal inputs, while comprising of one or more of the following steps:

I) means for measuring a closed-system temperature rate-of-change while energy sources are of line, to calculate the energy dissipated from the closed-system;

II) means for measuring a closed-system's temperature rate-of-change while one or more energy sources are on line, to calculate the balance of energy pumped into and dissipated from the system;

III) means for adding the amount of total energy dissipated (I) and the balance of energy pumped into the system (II) to calculate the energy pumped into a closed-system

IV) means for comparing the output of the energy sources (III) to that of the energy sources original (factory) output to calculate the closed- system energy source efficiency

V) means for calculating the inverse of the energy sources efficiencies (IV) to calculate the closed-system energy source wear-and-tear

VI) means for dividing the total energy dissipated (I) by the energy pumped into the system (III) to calculate the closed-system energy source load-factor;

VII) means for dividing the total energy dissipated (I) over a previously calculated (I)-value used as a reference to calculate the closed-system energy source load-change.