Smart thermostats: selecting and customising a low-cost solution for a system integrator

Customer and Challenge

A system integrator approached us to find a budget-friendly solution for automatic room heat control. Their request was related to the plans of the Lithuanian Ministry of Energy to reduce the indoor temperature to 19 degrees on weekdays and to 17 degrees on weekends. Other EU countries expect to take similar measures to save energy during the heating season.

Solution

We have reviewed and analysed the available solutions from Chinese factories to find the best solution to suit our customer's requirements, including possible delivery times and customisation options. We provided our client with an analytical table with a dozen selected devices, sorted by manufacturers, customisation options, SDK availability, and cost.

In the second stage, we have chosen smart thermostatic radiator valves as the most promising solution. Such devices measure the air temperature and regulate the flow of hot water flowing through them. Here are five selected models:

Model	ST-TVR1	TR-100	HTW-31RT-E	PS-RV06	PS-BRT-100
Manufacturer	Ningbo Red Belt Trading Co., Ltd.	Guangdong Chico Electronic Inc.	Hotowell International Co., Ltd.	Shenzhen Posher Electric Co., Ltd.	Shenzhen Posher Electric Co., Ltd.
Customisation options	Design + an app for orders of 5,000+ pieces	Design + an app for orders of 5,000+ pieces	Design + an app for orders of 5,000+ pieces	Design + an app	Design + an app
SDK	Yes	Yes	Yes	Yes	Yes
Remote control	Yes	Yes	Yes	Yes	Yes

As a result, we have selected the two most promising models: TR-100 and HTW-31RT. Here is the control interface in the TR-100 model:

^{Photo source: Ningbo Red Belt Trading Co., Ltd}
 

And here is the control interface in the HTW-31RT model and a possible integration scheme into the customer's system:

^{Photo source: Hotowell International Co., Ltd.}
 

Smart thermostatic radiator valves can be connected to any radiator with adapters. Both models can be customised (logo, box and app branding). The controls are managed via their mobile apps that can be customised and integrated into existing building monitoring and control systems. 

For example, the TR-100 model is used with the Tuya App (Smart Life) and a Smart Gateway that works via Tuya Smart's Bluetooth, Zigbee and Wi-Fi protocols. 

Zigbee is a high-speed data transfer protocol that enables instant transmission of information to a gateway when the sensor is activated. Both manufacturers provide their SDK after the purchase of samples. 

Outcome

We selected the best thermostat and are now ready to integrate it into the customer's system with the following tasks in mind: 

• To update the initial mobile app to control the heating system: localisation, branding and extra settings to display the required parameters only.
• To disable manual adjustment of the controllers, so that only administrators could manage the maximum values. 
• To supply up to 5000 customised controllers (thermostats).