A Smartbox as a low-cost home automation solution for prosumers with a battery storage system in a demand response program

G. Brusco, G. Barone, A. Burgio, D. Menniti, A. Pinnarelli, L. Scarcello and N. SorrentinoDepartment of Mechanical, Energy and Management Engineering, University of Calabria, Italy

II. THE CASE STUDYThis section illustrates a case study of a private household equipped with a home automation system, situated in a

rural area of Southern Italy. The electrical energy demand of local loads is satisfied by:

• 2kW photovoltaic plant;

• 2kW wind turbine;

• 1kWe/3kWt biomass boiler with Stirling Engine;

• 6kW 230V/50Hz connection to distribution grid;

• 3kW/4kWh lithium-ion battery energy storage system.

The contract that the end-user subscribed with the local retailer ratifies an electricity cost from 8am to 7pm equals to

0.159€/kWh and from 7pm to 8am equals to 0.152€/kWh.

Eleven electrical loads are considered: seven of them are non-schedulable loads and include internal and external

lightings, personal computers, TVs, a refrigerator, air conditioning; four of them are schedulable loads and include a

washing machine, an electric oven, a dish washer and a charging station for electric vehicles. The rated power, the

work cycle duration, the period during which the work cycle must be executed and the option interruptible/non-

interruptible for all schedulable load have been obtained by statistical surveys about the preferential habits of typical

end-users.

III. LABORATORY PROTOTYPEIn order to demonstrate the effectiveness and the feasibility of the proposed Smartbox, a prototype has been

realized and tested in the laboratory. Such a prototype has been tested in combination with:

• a software application which provides the input form (Fig. 1) ;

• a demonstration panel which represents a private household equipped with a home automation system (Fig. 2);

• a prosumer problem solver consisting in a personal computer on which Matlab software can runs (Fig. 3).

In order to solve the prosumer problem, input data are requested. To provide input data, the end-user utilizes a

software application through which he chooses the preferential start and end time for each schedulable loads.

The schedulable loads presented in the private household are represented by a demonstration panel equipped

with a Schneider Electric home automation system based on Konnex communication protocol (KNX).

The prosumer problem solver essentially is a service offered to all those prosumers operating in the demand

response program. In order to offer a high quality service, the solver knows the hourly energy price, the not

schedulable load profiles, the local solar and wind forecasts so to update the RES production forecast: on the

bases of this data, the solver calculates the optimal scheduling to minimize the electricity bill. In the laboratory,

prototype the prosumer problem solver is a personal computer with the software Matlab: the optimal scheduling

is calculated and sent via Internet to the Smartbox.

The paper presents an electronic device named Smartbox as a low-cost solution for those prosumers operating in a demand response program. Given that a processing resource

in the cloud optimally calculates the loads scheduling one day-ahead on the basis of the electricity prices and the load and weather forecasting , the aim of the Smartbox is to

receive and to act the loads scheduling. A prototype of a Smartbox using an Arduino MEGA 2560 has been realized and tested in the laboratory, in combination with a

demonstration panel which represents a private household equipped with a Schneider Electric home automation system based on Konnex communication protocol (KNX).

I. USER INPUT FORM and

DEMAND RESPONSE Demand response is an articulated program of

actions that allows end-users to modify their

electrical load profiles. The optimal scheduling

obtained by time-shifting electrical loads, is

determined in response to price signals,

financial incentives, environmental conditions

and reliability signals.A focus is set on the

decentralized scheme, where each prosumer

autonomously takes decisions based on own

requirements and aims.

PROSUMER PROBLEMIn this section the prosumer problem for home

applications with appliances, local generators

and a battery energy storage system is

illustrated. A linear optimization has been used

to solve the problem, returning the optimal

scheduling for the day ahead,

PROSUMER PROBLEMIn this section the prosumer problem for home

applications with appliances, local generators

and a battery energy storage system is

illustrated. A linear optimization has been used

to solve the problem, returning the optimal

scheduling for the day ahead,

1 2 3

THE SMARTBOXThe Smartbox is a low-cost electronic device, web connected

to the local area network; the aim of the Smartbox is to

receive the solution of the prosumer problem and to act the

optimal scheduling of the electrical loads.

A laboratory prototype of a Smartbox has been realized with

an Arduino Mega 2560; also a LCD display 4x20, a Ethernet

Shield and a sim Tapko KNX have been used (Fig. 4).

Received the solution on hourly basis, the Arduino Mega

2560 manages the switching-on and off of schedulable loads,

sending commands to the sim Tapko KNX that converts them

into KNX control frames, using the konnex protocol.

In order to implement the optimal scheduling, the sim Tapko

KNX sends control frames to schedulable loads writing on the

communication bus of the KNX home automation system.