YANMAR Technical Review

Offering of Total Energy Services: Feature introduction of Y-EMS

September 30, 2022


Efforts to reduce energy consumption are critical for achieving ‘Carbon Neutrality’.
Along with gas heat pumps and cogeneration systems, the equipment required to achieve carbon neutrality also includes energy management systems for more efficient operation and energy services for maintenance and energy diagnostics. Through these efforts, Yanmar Energy System Co., Ltd. is operating as a total energy services company.
This article introduces these total energy services together with the functions of the energy management system and example applications of energy diagnostics.


Together with reducing GHG emissions, efforts to reduce energy consumption are critical for achieving carbon neutrality.
Operating as a total energy services provider, Yanmar Energy System Co., Ltd. engages not only in manufacturing and sales of equipment for efficiently supplying heat and electric power vital to modern society, but also in providing design, installation, maintenance, and operational services covering all aspects of the systems that use this equipment.
Yanmar’s cogeneration systems and gas heat pumps (GHPs) are helping customers to improve energy efficiency in their offices, hospitals, hotels, and other commercial buildings. Likewise, the using of carbon-neutral biofuels in cogeneration is helping to reduce CO2 emissions, and this practice has been adopted at many food production, wastewater processing, and other plants.
While this equipment is capable of operating efficiently on a standalone basis, overall plant efficiency can be further enhanced by aggregating and operating all equipment as an integrated system. Yanmar has developed its energy management system (Y-EMS) to achieve this efficiency enhancement. Y-EMS incorporates functions for energy visualization, the automatic control of equipment, and data management. These provide optimal plant-wide operation based on collected information. This article describes the features of Y-EMS and the total energy services in which it is utilized.



The Y-EMS energy management system aggregates the equipment at a site or building and handles its operation and management (Fig. 1). Along with Yanmar product support, its scope encompasses a broad range of equipment that supplies or consumes energy. Supported energy-supplying equipment includes cogeneration systems, boilers, chillers, and absorption water coolers and heaters. Loads include fans, electric motors, and dryers. The system also supports a wide variety of sensors to enable the monitoring of many different types of equipment. The main functions of Y-EMS are as follows.

[1] Energy visualization

  • These functions enable the detailed visualization of how each item of equipment is operating by aggregating the collection of many different types of data (including electric power, temperature, flow rate, pressure, water or fuel level, equipment running /stopped and valve open/closed status signals).
  • Easy access to the required information is provided by screens designed to handle the different ways in which equipment is managed (screens that aggregate information for specific purposes).

[2] Automatic control of equipment

  • These functions perform optimal automatic control of equipment overall. Operation can be optimized for cost, CO2 emissions, or primary energy consumption.
  • Demand control is available to avoid exceeding contracted electricity use.
  • Customized control enables machinery to be controlled based on collected information using simple control logic.

[3] Centralized equipment management (reporting)

  • Operational data from across the plant can be managed all in one place. This eliminates the task of compiling operational data from different items of equipment.
Fig. 1 Example Equipment covered by Y-EMS
Fig. 1 Example Equipment covered by Y-EMS

2.2.Function Overview

Table 1 lists the main functions of Y-EMS, which are divided into visualization, automatic control, and reporting (data management).

Table 1 Main Functions

Function Description
Visualization Home
  • Aggregates display of current supply and demand for electricity and thermal energy
    Summarizes energy use across all equipment
  • Displays previous-day energy use for comparison with current performance
    Highlights differences between current usage and previous day at a glance
  • Displays layout of the equipment to be monitored
    Provides a quick view of energy flows and quantities
  • Displays details of equipment and system failures
    Enables easy identification of equipment failures and failure details
  • Graphs of electricity and thermal energy use for different equipment over time
    Enables easy identification of daily operating status of each item of equipment
Automatic control Optimization control
  • Uses past operational data to predict loads so that equipment can operate optimally according to the load
    Predicted loads can also be entered manually to enable optimal operation
Demand control
  • Controls energy supply and load equipment to avoid exceeding contracted electric power use
Customized control
  • Can control equipment in accordance with user-specified control logic
    Can control machinery (such as pumps) based on monitored data (such as temperatures)
  • Operates equipment according to a specified schedule
    Can avoid wasteful operation by operating equipment on a schedule according to the load
Reporting Equipment operation reports
  • Compiles time-series data such as electricity and thermal energy use for each item of equipment
    Generates monthly reports based on this data

[1] Visualization

Visualization is an important function for understanding, analyzing, and improving overall energy supply and demand across all equipment. To make it easy to obtain a plant-wide equipment overview, Y-EMS screen designs aggregate and classify data by specific purpose. Table 1 lists some of the most commonly used screens for equipment management.

Fig. 2 Example Home Screen
Fig. 2 Example Home Screen

Fig. 2 shows an example of the home screen. The screen is arranged in three rows, with the top and middle rows showing supply and demand for electrical and thermal energy, respectively. The donut charts show how much of current electrical and thermal demand is being supplied by the respective energy supply systems, indicating the operational status of both supply and load equipment at a glance. The bar graphs, in turn, provide a rapid indicator of higher or lower utilization by comparing the day’s electrical and thermal energy use with that of the previous day. The bottom row shows fuel consumption for various fuels, primary energy use, and CO2 emissions. As in the upper and middle rows, the bar graphs show the increase or decrease in the day's usage compared with the previous day, at a glance.

Fig. 3 Example Layout Screen (Electrical Equipment)
Fig. 3 Example Layout Screen (Electrical Equipment)

Fig. 3 shows an example schematic screen. Layout screens show the layout of the equipment connected to Y-EMS, with separate screens for electric power and thermal energy. Equipment status (stopped, running, or failure) is indicated by an icon for ease of viewing. The operational status of equipment is also indicated by displaying consumption or supply data below each icon.
Other screens are provided for the various applications listed in Table 1, enabling these provide a simple overview of all equipment.

[2] Automatic control

These functions provide optimization, demand control, customized control, and scheduling functions to ensure that all of the equipment operates in a manner that is efficient from the perspective of the plant as a whole.
Optimization control uses historic data as a basis for predicting supply and demand and then operates equipment accordingly.
Demand control operates equipment in a way that avoids exceeding contracted electricity use. If the amount of electric power being drawn from the grid threatens to exceed the predetermined limit, this function adjusts the operation of the cogeneration system or loads to prevent this from happening.
Custom control provides the ability for users to specify their own control logic. Potential examples include turning pumps on and off or adjusting valves based on temperature values, or using level gauge readings as a basis for valve control.

[3] Reporting

Fig. 4 shows an overview of the reporting function that enables data that was previously spread across different equipment to be consolidated in Y-EMS. By automating this process, the reporting function eliminates the time spent on tasks like data collection and processing. It also reduces the amount of work required to produce or revise maintenance plans and fuel purchasing schedules. The data collected by Y-EMS is stored at the contact center and can be used to generate monthly reports in customer-specified formats.

Fig. 4 Overview of Reporting
Fig. 4 Overview of Reporting

2.3.Example Application

This section describes an example use of customized control to implement control logic for specific customer equipment. As this example demonstrates, customized control can specify how to operate under various simple conditions.

Example case
This example involves a system that links the cogeneration system's and hot water pump's operations to supply hot water to a storage tank (see Fig. 5). In this example, running the hot water pump before the cogeneration system has warmed up (such as at system startup) will not deliver any heat. Accordingly, as both the cogeneration cooling water and tank temperatures are monitored, these can be used to determine when to run the pump (the “Conditions for pump operation” in the figure). This results in more efficient operation as the pump does not start to run until after the cogeneration system has warmed up.

Fig. 5 Example Use of Customized Control
Fig. 5 Example Use of Customized Control

In the above example, if the heat demand exceeds what the cogeneration system can supply, the efficiency of overall equipment operation could be improved by upgrading the cogeneration system and operating it in a way that ensures it has sufficient capacity to meet the heat demand. This is because Y-EMS can only operate systems within their capabilities (between the upper and lower limits). That is, optimal operation by Y-EMS is limited to this range and a heat supply system that has insufficient capacity to meet demand can, at best, only operate at its upper limit. Upgrades to the capacity of supply systems have the potential to increase plant-wide equipment efficiency, so Yanmar offers energy diagnostic services that analyze data collected by Y-EMS and suggest improvements such as changes to system specifications.

3.Energy-saving Diagnostic Services


[1] Highly precise analysis

  • Using data collected by Y-EMS makes it possible to identify when changes occur and to conduct analysis that takes account of these changes (such as analysis of equipment aging or the prediction of performance degradation).

[2] Extensive choice of improvement methods

  • Using extensive data that Yanmar corrected makes it possible to refer a wide range of relevant past examples (allowing it to reference or re-use previous work).

[3] Easy verification of improvement benefits

  • It is easy to verify the benefits of improvements as Y-EMS can be used for operation and management even after equipment is upgraded.

3.2.Example Application

In this example of an energy-saving diagnostic review conducted using data collected by Y-EMS, plant-wide equipment energy savings was achieved using collected data alone, without using Y-EMS for equipment control (using monitoring functions only).

Example case
The review considered a facility equipped with an air conditioning system that was operated according to a schedule. In this case, the system handled its own control and Y-EMS was only used for monitoring. To provide a safety margin, the system was started slightly before the facility it serves (the air conditioning load). When data was collected using Y-EMS, it became apparent that this time margin was more than sufficient to meet the load. Accordingly, energy could be saved by starting the system slightly later.


Since it first went on the market several years ago, Y-EMS has been installed at several dozen sites where it has helped cut costs, save energy, and reduce CO2 emissions. The system has a proven energy savings of 10% through optimal equipment operation and improved energy-savings diagnostics (Fig. 6). With energy concerns and global warming set to become more challenging than ever, Yanmar intends to build on its strength in providing total energy services by regularly upgrading Y-EMS and its energy diagnostic services while also persevering with development work to ensure that it can continue to offer effective solutions.

Fig. 6 Case Study of Energy Consumption Reduction
Fig. 6 Case Study of Energy Consumption Reduction


The original technical report is written in Japanese.

This document was translated by Innovation & Technology Division, Technology Strategy Division.


Development Division

Akihiro Hara