The ESM™ is a system of micro-computer digital optimization modules specifically designed to reduce the electricity consumption (kWh) and maximum demand (KW) of refrigeration and air conditioning compressors by 15% to 20% while maintaining temperature performance.

The ESM™ is designed to interface with all types and makes of air conditioning and refrigeration controllers from the simple thermostat single condensing systems to the most sophisticated computer based multiple compressor parallel systems. The ESM utilizes world wide exclusively copyrighted software that has been developed over 20 years to augment existing building and refrigeration control systems.

The major function of the ESM™ is to optimize the performance of air conditioning and refrigeration compressors while operating within the control parameters of the existing primary controller.

In addition to its exceptional energy saving capabilities, the ESM™ has several other attributes:

• The ESM™ reduces compressor run time by 15% - 50% and in so doing extends compressor life. Therefore the ESM™ provides cost reductions to both operating and capital budgets.
• Using the ESM™ restricts "short cycling" and ensures warranty compliance by only allowing for a maximum of 2 saving Off periods per 30 minute operating cycle. The ESM™ is installed in the control circuit in series with and after the thermostat. Because the ESM™ is no more invasive than a thermostat there are no issues with the compressor's warranty.
• Because the ESM™ complements, but does not replace the primary controls, an accurate evaluation of the ESM performance can be measured at any time after installation of the ESM™ by switching the ESM™ off and comparing the kWh consumption with a similar period with the ESM™ operating. This is critical to qualifying for any of the government or utility rebate programs.

Installation is relatively easy and can be carried out by an electrical or mechanical trade's person, normally in less than a day. The ESM's™ are connected in the control circuit in series with the existing compressor controls.

Network Controller (LNC)

The Network Controller (LNC) contains the Central Processor Unit that provides control for a maximum of eight channels through four, two channel System Interface Modules (SIM). Within a global system one Network Controller is designated as the Global Network Controller (GNC) undertaking the task of managing communication through the RS485 network and also any external communication via aRS232 port.

The Network Controller has three analogue and two external digital inputs that can be configured for temperature or suction pressure measurement. The values of these two inputs determine the degree of compressor optimization that can be applied to the Local Network.

The Network Controller controls the switching and communication functions of the local network. The local network will always consist of one Network Controller and at least one SIM. The keypad on the Network Controller enables configuration of the local

network, access to data and bypass selection. The relevant data and information are shown on the display.

In a Global System the selection of the Global or Local control duty of the Network Controller is also achieved through the keypad.

The keypad on the Network Controller enables access to ten menu items:

Selecting "Multiplex" mode enables the Network Controller to manage a maximum of eight parallel connected compressors. Selecting Simplex mode enables the management of up to eight independent cooling loads.

The Energy Saving Module System 4000™ is designed to be "fail safe". In the unlikely event of a system fault each input/output channel will automatically bypass to ensure continuous operation of the air conditioning and refrigeration equipment. Sets of normally open, voltage free alarm contacts provide remote indication of a system override or channel bypass.

System Interface Module (SIM)

The SIM is connected in series with the air conditioning or refrigeration control circuit to directly control the compressor operation. Each SIM has two electrically separate, independent channels with normally open and normally closed switching.

A 24 pin male connector on each side of the SIM enables direct, side-by-side connection to the Network Controller and other SIM's.

Each channel has a provision for an external override, which can be activated by any type of external switching device such as a thermostat or pressure switch.

LED indicators show the status of the input, output and bypass:

How are saving achieved?

Conventional controls, including the most sophisticated Building Management Systems (BMS') and state-of-the-art refrigeration controls, operate only on reaching pre-programmed fixed (static) values to switch compressors off and on or adjust capacity. When the measured medium is within the dead band the BMS and controllers remain idle until a specific set value is reached. They do nothing to dynamically measure the heat

load and adjust the control differential in proportion to the cooling demand or to dynamically control the cycle rate of the compressors. In most cases they do not perform predictive analyses as the ESM™ does.

The ESM™ microcomputer records the absolute switching values of the primary controller and also measures the 'rate of change' of both the rise and fall of temperatures during the operating cycle of the compressors. With this data the ESM™ computes a reference heat load to match the cooling capacity and then calculates variable operating parameters (we call this Load Proportional Differential Adjustment or LPDA). LPDA minimizes compressor operation within the absolute switching values, with a resultant reduction in refrigeration and air conditioning compressor run time, reduced electricity consumption (Kwh) and maximum demand (Kw/KVA) as well as the maintenance of the required temperature.

Compressor Optimization

What Does "Compressor Optimization" Mean?

A refrigeration compressors' capacity to remove heat is directly proportional to the operating temperature. That is the higher the controlled temperature, the higher the suction temperature (evaporator temperature), the faster the rate of heat removal.

A refrigeration cycle is a dynamic changing cycle. From the time the compressor commences to run until it stops, the suction pressure, evaporator pressure, the rate of heat exchange, refrigerant flow and many other factors are all continuously changing.

A refrigeration system is at maximum efficiency immediately after the compressor starts. The efficiency is progressively reduced as the temperature reduces. By adjusting the suction pressure over a narrow band it is possible to maximize the compressor performance increasing cooling capacity by more than 30% and achieve compressor optimization.

ESM™ Optimization Programs

The System 4000 ESM™ operates two proprietary programs to achieve a reduction in compressor operation without affecting the cooling capacity of the refrigeration system. The programs have the acronyms LACRA and PDA1. 1LACRA and PDA are copyright protected and the exclusive property of Smartcool International

LACRA is L oad A daptive C ycle R ate A djustment. The number and frequency of the total compressor stops and starts over the whole control differential is monitored and stored by this program. The start or stop action is logged by the LNC and referenced to a particular temperature point.

PDA is P roportional D ifferential A djustment. Conventional controls operate on absolute pre-programmed static values, ie. The Switch On and Off value is fixed and not variable. Using the information gathered by the LACRA program together with the data from the analogue and digital optimization inputs, either thermostatic or suction pressure enables the LNC to calculate a more effective control differential that will reduce compressor operation and maintain the controlled variable within the required range.

The Local Network Controller (LNC) adjusts the operational parameters each 30 minute period based on the data collected on the previous 30 minute period and historical data.

Routines

The software package also consists of a number of other sub-routines that are automatically enabled by the LNC dependant on the number of loads connected, the analogue input and digital input values.

All programs are designed to achieve a minimum saving level of 15%, which can be incrementally maximized, to 50% dependant on compressor cycle rate and temperature conditions.

In addition to reducing the kWh consumption of refrigeration systems the programs also analyze the compressor operation each 30 minutes to achieve a reduction in the measured maximum demand KVA or KW.

The reduction kWh is achieved by strategically and selectively switching off the controlled loads. The off period in any one 30 minute period will be a minimum of 4 minutes to a maximum of 18 minutes. In most cases a controlled load will only be switched once in any 30-minute period. The maximum cycle rate of any load on the ESM™ is twice per 30-minute period.

Multiplex Operation

The Multiplex program is selected for parallel-connected loads such as multiple compressors on common suction and discharge manifolds, compressors with solenoid capacity control or multiple liquid line solenoid valves or a combination of all of the above.

Three sub-routines are included in the program which are automatically enabled when one, two or more than two System Interface Modules are connected to an LNC.

Simplex Operation

This program enables control of single independent loads each having their own thermostat or other control.

The Simplex program operation is the same for any number of SIM's connected to the LNC. A Saving Off period is applied to each operational channel once each 30 minute period.

To achieve a significant maximum demand reduction the Saving Off periods will be staggered over the whole 30-minute period dependant on the temperature and cycle rate of each load.

Chiller Programs

Most modern chillers either with screw compressors or reciprocating compressors are fitted with Micro-Processor Chiller Management Systems that usually allow a third party interface to modify the chiller capacity control.

Smartcool has developed a number of programmable logic controls (PLC's) for the ESM™ that enable direct interface with the leading brands of chillers. The ESM™ uses either a digital or analog interface.

Using a direct interface with the chiller management system ensures the integrity of the chiller safety and management systems complies with the chiller manufacturers warranty conditions and is usually more cost effective than hard wiring to the chiller control circuits.

The chiller control program applies two saving periods each 30 minutes. The saving periods will be a minimum of 4 minutes to a maximum of 14 minutes. The duration of the saving period is determined by the LNC based on the chiller load level and the rate of change of the return chilled water temperature.

Communication Centre Software

The ESM™ Communication Centre Software is used to remotely monitor the operation of any ESM System 4000™ installation.

As many as 300 LNCs at an installation (on the network) can be interconnected through an RS485 communication link to produce a Global Network. By connecting the LNCs through the RS485 system only one telephone modem is required for each site. One LNC is then connected to a modem cable via the RJ45 connector socket on the front panel of the LNC.

The Communication Centre Software can be connected the internet via Direct Connection, Landline Modem or GSM Modem.

Once connected, operational data such as 'savings settings' and 'saving priority', set up information as well as logging data for each LNC on the network can be accessed, monitored, collected and amended remotely via the internet from anywhere in the world.

Rebate Programs Available

The ESM™ has been designed in order to qualify for all utility and government rebate programs. Specifically the ESM's™ "on and off" feature allows it to be switched out of the compressor circuit for easy savings verification which is a requirement for most rebate programs. Additionally an ESM™ installation includes the completion of the following standard evaluation procedure to determine the energy reduction performance and temperature maintenance of the ESM™.

Evaluation Procedure

Methodology: An Energy Logger will be installed on the electrical service to the air conditioning or refrigeration compressor. The Logger will record the amperes, KW, KVA, & Kwh. In addition a temperature data logger will be installed to monitor the ambient temperature and the temperature of the controlled medium, either chilled water, return air temperatures or conditioned space temperatures.

The air conditioning and / or refrigeration plant will be operated alternate weeks with the Energy Saving Module™ switched on and off to achieve a seven day comparison. The duration of the trial is normally for two weeks.

The loggers are set to provide a print out every hour and summated every 24 hours. This provides a "weekday" comparison, for example compare Monday week 1 to Monday week 2. The data from the logger is downloaded on site at the conclusion of the evaluation.

The Loggers: The Energy Logger will either be an ACR Model SR003, a Power Site PS250 Meter or a Pacific Technologies E Logger or equivalent. The logger is non-intrusive, does not require any interruption to the supply or the disconnection of any power cables. The loggers utilize clamp on current transformers and voltage probes to collect the relevant data. All loggers have a sampling rate of 8 seconds and can be programmed to summate and print the data for any time interval. The loggers are fully approved to Australian Standards, USA Underwriters Laboratories (UL) CSA and C.E. requirements.

This evaluation will also form the basis of an application to the relevant utility or government office to access any rebate program available for the installation of the equipment. If you wish Smartcool can apply for the rebate your behalf in exchange for a fee that is equal to a percentage of the funds received.

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