Wireless sensors and IoT platform for intelligent HVAC control

Energy consumption of buildings (residential and non-residential) represents approximately 40% of total world electricity consumption, with half of this energy consumed by HVAC systems. Model-Based Predictive Control (MBPC) is perhaps the technique most often proposed for HVAC control, since it offers an enormous potential for energy savings. Despite the large number of papers on this topic during the last few years, there are only a few reported applications of the use of MBPC for existing buildings, under normal occupancy conditions and, to the best of our knowledge, no commercial solution yet. A marketable solution has been recently presented by the authors, coined the IMBPC HVAC system. This paper describes the design, prototyping and validation of two components of this integrated system, the Self-Powered Wireless Sensors and the IOT platform developed. Results for the use of IMBPC in a real building under normal occupation demonstrate savings in the electricity bill while maintaining thermal comfort during the whole occupation schedule.QREN SIDT [38798]; Portuguese Foundation for Science & Technology, through IDMEC, under LAETA [ID/EMS/50022/2013

Temperature controlled light-emitting diode lamp for photovoltaic rural applications

In recent years, interest in light-emitting diode (LED) lighting has been growing because of its high efficacy, lifetime and ruggedness. This paper proposes a better adaptation of LED lamps to the technical requirements of photovoltaic lighting domestic systems, whose main quality criteria are reliability and that behave as voltage power supplies. As the key element of reliability in LED lamps is temperature, a solution is proposed for driving LED lamps using voltage sources, such as photovoltaic system batteries, with a control architecture based on pulse width modulation signal that regulates the current applied according to the LED lamp temperature. A prototype of the LED lamp has been implemented and tested to show its good performance at different temperatures and at different battery voltages

A compact energy harvesting system for outdoor wireless sensor nodes based on a low-cost in situ photovoltaic panel characterization-modelling unit

This paper presents a low-cost high-efficiency solar energy harvesting system to power outdoor wireless sensor nodes. It is based on a Voltage Open Circuit (VOC) algorithm that estimates the open-circuit voltage by means of a multilayer perceptron neural network model trained using local experimental characterization data, which are acquired through a novel low cost characterization system incorporated into the deployed node. Both units—characterization and modelling—are controlled by the same low-cost microcontroller, providing a complete solution which can be understood as a virtual pilot cell, with identical characteristics to those of the specific small solar cell installed on the sensor node, that besides allows an easy adaptation to changes in the actual environmental conditions, panel aging, etc. Experimental comparison to a classical pilot panel based VOC algorithm show better efficiency under the same tested conditions

Design of a wireless monitoring system based on the ZigBee protocol for photovoltaic systems

This thesis was submitted for the degree of Master of Philosophy and awarded by Brunel University.This work deals with the possibility of using the promising technology of wireless sensor networks (WSN) in the field of photovoltaic (PV) plant supervising and monitoring. The knowledge of the status and good working condition of each PV module separately as well as of any component of the PV system will guide in a more efficient way of power management. This work will concentrate on monitoring and controlling as well as healthy operation control of PV panels separately. Data logging will be also available and can be used for reference or statistical purposes. The nature of wireless sensor networks (WSN) offers several advantages on monitoring and controlling applications over other traditional technologies including self-healing, self-organization, and flexibility. The versatility, ease of use, and reliability of a mesh network topology offered by the ZigBee technology that is based on the IEEE 802.15.4 standard, are used in this work to offer the maximum of its capabilities on the system being presented. A set of sensors attached on each PV panel are connected to a wireless ZigBee module. Each PV panel has its own ZigBee device located at its back side. All ZigBee devices forms a network with all the necessary devices of the ZigBee protocol included, such as end devises (RFD), a router (FFD), and a coordinator (COO). An extra ZigBee device might optionally be used to serve the whole system as an Ethernet gateway for making the system able to be connected to the internet. The factors that are being monitored are the panel‟s temperature, the output voltage, and output current. At the router device that operates as a parent for all the end devices, extra monitored factors are the air dust concentration, current irradiance and also the angle of the PV array (in the case of tracking system use).Two controlling outputs (relays) are located at the router device offering the capability of controlling the motors or the actuators of a tracking system

Charge controller for solar panel based charging of lead-acid batteries

Tato diplomová práce se zabývá návrhem a realizací regulátoru pro použití v solárním systému s větším počtem olověných akumulátorů. Takový regulátor umožňuje nezávislé připojení a řízení nabíjení většího počtu akumulátorů různého stáří a parametrů. To je v kontrastu s řešeními obsahujícími jedno připojení pro více baterií připojených paralelně, kde se míchání baterií různého druhu a stáří nedoporučuje. Tento regulátor nabízí vysokou škálovatelnost skladování energie v solárním systému. Umožňuje také používat starší baterie s novými, místo nutnosti staré baterie nahradit, když jejich kapacita klesne pod požadovanou úroveň. V této práci jsou podrobně popsány požadavky, návrh hardwaru a softwaru a implementace regulátoru s nominálním výstupním proudem 20A pro pět 12V olověných baterií. Práce popisuje také další funkce, stejně jako alternativní návrhy a algoritmy. Důležitá část práce se zabývá designem spínačů pro velké proudy, ochrany proti zkratu a obvodů pro měření stejnosměrného proudu. Správná funkčnost regulátoru byla ověřena měřením.This thesis deals with the design and implementation of a charge controller for multiple lead-acid batteries to be used in a solar system. Such controller enables an independent connection and charge control for each of more batteries with possibly different age and parameters. It is in contrast with solutions with one connection for multiple batteries connected in parallel, where mixing different battery types or ages is not recommended. This controller offers very high scalability of energy storage in solar system. It is also possible to use older batteries together with new ones instead of having to replace the old batteries when their capacity falls below required level. The requirements, hardware and software design along with the implementation of such controller with 20A nominal output current for five 12V lead-acid batteries are discussed in detail in this thesis. Additional features, alternative designs and algorithms are discussed as well. An important part of the work concentrates on high current switch design, short circuit protection as well as circuit for DC current measurement. Correct functionality of the implemented controller has been verified by measurements.

Implementation of sequential design based water level monitoring and controlling system

In currently decades, water usage either for domestic or commercial purposes is facing critical conditions which negatively affects the sustainability of our environment. From this point of view, reducing water consumptions will participate in the solution of water saving. Monitoring and controlling the tank water level are important functions which effect and work on reduction of water consumption.  Many studies in literature focus on proposing a high performance water level monitoring and controlling systems based on either computerized units or microcontroller units. However these systems are characterized by complexity and high cost. In this paper, a highly flexible implemented electronic system is introduced based on sequential design by using general purpose discrete components. The proposed system present simple design of water level sensing stage, in addition, this paper showing full design, simulation, and implementation steps of an automation system which is able to control switching the state of the water pump in accordance to the current level of water in the tank

OpenHumidistat:Humidity-controlled experiments for everyone

Humidity control is a crucial element for a wide variety of experiments. Yet, often naive methods are used that do not yield stable regulation of the humidity, are slow, or are inflexible. PID-based electropneumatic humidistats solve these problems, but commercial devices are not widespread, typically proprietary and/or prohibitively expensive. Here we describe OpenHumidistat: a free and open-source humidistat for laboratory-scale humidity control that is affordable (<500 EUR) and easy to build. The design is based around mixing a humid and dry air flow in varying proportions, using proportional solenoid valves and flow sensors to control flow rates. The mixed flow is led into a measurement chamber, which contains a humidity sensor to provide feedback to the controller, to achieve closed-loop humidity control

PV monitoring system for a water pumping scheme with lithium-ion battery using free open-source software and IoT technologies.

[EN] The development of photovoltaic (PV) technology is now a reality. The inclusion of lithium-ion batteries in grid-connected PV systems is growing, and the sharp drop in prices for these batteries will enable their use in applications such as PV water pumping schemes (PVWPS). A technical solution for the monitoring and tracking of PV systems is shown in this work, and a novel quasi-real-time monitoring system for a PVWPS with a Li-ion battery is proposed in which open-source Internet of Things (IoT) tools are used. The purpose of the monitoring system is to provide a useful tool for the operation, management, and development of these facilities. The experimental facility used to test the monitoring system includes a 2.4 kWpk photovoltaic field, a 3.6 kVA hybrid inverter, a 3.3 kWh/3 kW lithium-ion battery, a 2.2 kVA variable speed driver, and a 1.5 kW submersible pump. To address this study, data acquisition is performed using commercial hardware solutions that communicate using a Modbus-RTU protocol over an RS485 bus and open software. A Raspberry Pi is used in the data gateway stage, including a PM2 free open-source process manager to increase the robustness and reliability of the monitoring system. Data storage is performed in a server using InfluxDB for open-source database storage and Grafana as open-source data visualization software. Data processing is complemented with a configurable data exporter program that enables users to select and copy the data stored in InfluxDB. Excel or .csv files can be created that include the desired variables with a defined time interval and with the desired data granularity. Finally, the initial results of the monitoring system are presented, and the possible uses of the acquired data and potential users of the system are identified and described.This research was funded by Universitat Politècnica de València (UPV; Program ADSIDEO-cooperation 2017, project titled ¿Characterization of sustainable systems for the pumping of water for human consumption in developing regions and/or refugee camps in Kenya through the implementation of isolated photovoltaic systems with new generation lithium-ion batteries¿).Gimeno Sales, FJ.; Orts-Grau, S.; Escriba-Aparisi, A.; González Altozano, P.; Balbastre Peralta, I.; Martínez-Márquez, CI.; Gasque Albalate, M.... (2020). PV monitoring system for a water pumping scheme with lithium-ion battery using free open-source software and IoT technologies. Sustainability. 12(24):1-28. https://doi.org/10.3390/su122410651S128122

Development of a Real-Time Microchip PCR System for Portable Plant Disease Diagnosis

Rapid and accurate detection of plant pathogens in the field is crucial to prevent the proliferation of infected crops. Polymerase chain reaction (PCR) process is the most reliable and accepted method for plant pathogen diagnosis, however current conventional PCR machines are not portable and require additional post-processing steps to detect the amplified DNA (amplicon) of pathogens. Real-time PCR can directly quantify the amplicon during the DNA amplification without the need for post processing, thus more suitable for field operations, however still takes time and require large instruments that are costly and not portable. Microchip PCR systems have emerged in the past decade to miniaturize conventional PCR systems and to reduce operation time and cost. Real-time microchip PCR systems have also emerged, but unfortunately all reported portable real-time microchip PCR systems require various auxiliary instruments. Here we present a stand-alone real-time microchip PCR system composed of a PCR reaction chamber microchip with integrated thin-film heater, a compact fluorescence detector to detect amplified DNA, a microcontroller to control the entire thermocycling operation with data acquisition capability, and a battery. The entire system is 25 × 16 × 8 cm(3) in size and 843 g in weight. The disposable microchip requires only 8-µl sample volume and a single PCR run consumes 110 mAh of power. A DNA extraction protocol, notably without the use of liquid nitrogen, chemicals, and other large lab equipment, was developed for field operations. The developed real-time microchip PCR system and the DNA extraction protocol were used to successfully detect six different fungal and bacterial plant pathogens with 100% success rate to a detection limit of 5 ng/8 µl sample