Control of industrial ventilation and cogeneration unit in city pools

References

The Czech company implementing energy-saving projects uses Unipi controllers to control and monitor the industrial ventilation system together with the cogeneration unit of the city swimming pools in Hustopeče.

The Czech company Amper Savings a.s., part of the Amper Energy Group, provides energy services, including implementing energy-saving projects using the latest technologies for optimizing energy management. The company’s specific area of interest are EPC projects (Energy Performance Contracting), i.e. the provision of energy services with a guaranteed result. This service consists of the company guaranteeing a reduction in energy consumption, which will be reflected in savings in operating costs. These savings are then used to repay the initial investment of the project.

Problem

One of the EPC projects that the company dealt with was the long-term energy-inefficient building of the city indoor swimming pool in Hustopeče. Originally outdated and spatially large switchboards, without the possibility of remote monitoring, had to be replaced with new ones. The existing ones required long-term and time-consuming manual maintenance, so it was necessary to choose reliable control units that would solve these problems. Requirements for new controllers included:

enabling remote monitoring and thus streamlining the maintenance of the entire project
simple wiring with respect to space and connected technologies
reliability to guarantee energy savings
secure connection of the control system with the Mervis SCADA cloud service
the possibility of further expansion of the entire project in the future

Solution

Based on the requirements of the project, the company selected Unipi control units from the Axon production line (M525 and L525; replaced by the fully compatible Patron M527 and L527 models) and from the Extension series (xS51, xS11, xG18).

"An ideal and cheap solution, where it was enough to use only Extensions connected to the main unit, instead of the original large switchboards."
– Martin Hauser; Head of the implementation center

The project involves the management of two indoor swimming pools, including their facilities (adjacent areas, changing rooms, etc.) and a large outdoor pool area (five pools with attached attractions such as water slides and waterfalls). All this using a boiler, cogeneration unit, solar panels, and industrial ventilation. In this case, Unipi controllers ensure that the management of such a system is efficient and energy-saving.
Using a system of digital and analog sensors (1-Wire, resistance sensors, etc.), the PLC units read the values of:

water temperature in swimming pools
air temperature in indoor areas and pool facilities
energy consumption/supply
humidity in indoor areas and pool facilities
gas consumption by the cogeneration unit
performance of the solar panels

Unipi controllers control the boiler and cogeneration unit using the Modbus protocol and control the use of energy from solar panels. The biggest advantages of the Modbus protocol are relative simplicity and low demands on system resources.

"We definitely prefer Modbus. The more data the better. ”
– Martin Hauser; Head of the Implementation Center

Thanks to this connection and based on the data obtained from the sensors, Unipi PLCs can economically control:

heating in the facilities and adjacent areas to each pool
water heating in swimming pools using a boiler, cogeneration unit, and solar panels
industrial ventilation for dehumidification

As a software solution, the project uses the Mervis system, an officially supported complete platform for Unipi products, including:

Mervis IDE (Integrated Development Environment) - for creating, debugging, and remote management of control programs for Unipi controllers.

"The important thing is that we program the project exactly as we need it."
– Martin Hauser, Head of the Implementation Center

Mervis SCADA (Supervisory Control and Data Acquisition) - a cloud service for remote dispatching, control, and analysis of historical data with the ability to monitor and control all connected systems regardless of their location in a clear graphical interface. Thanks to the use of Mervis SCADA, the company can monitor any intervention in the project and, based on historical data, also guarantee economic results.

Mervis Proxy (remote access and management) - a secure Internet connection from anywhere in the world, without the need for VPN, public IP addresses, or complex network configuration.

Next steps

In the future, the company plans to expand the project with pumps that would be controlled by another control unit module. Due to the saving of space in switchboards thanks to Unipi units, it is possible to easily add this future module to an existing installation.