The cooling and energy saving effect of landscape design parameters of urban park in summer: A case of Beijing, China

Urban green spaces have been demonstrated to bring environmental benefits from the distinctive effects of various landscape parameters. The current study investigates the cooling and energy saving effect of landscape parameters in an urban park of Beijing during a hot summer. Continuous in-site microclimate data of individual parameters including grass, water body, tree and artificial shading device (including Chinese style pavilion) and certain combination like grass + tree, water body + tree and shading device + tree were collected. Thermal perception of people caused by each parameter was studied according to both the measured data and thermal sensation votes from questionnaire survey. Based on those field measurements, the heat reduced and thus the energy saved by each parameter are estimated. The results indicate that manmade shading device performs the best cooling and energy saving effect among those individual parameters, and shading device + tree shows the optimal effect among all the chosen ones. The calculated objective thermal discomfort indexes show certain deviation from the real responses of the visitors. The heat reduced by each landscape parameter during a measuring period of 6 h from 10:00 to 16:00 h in the current case sequence to an order of water body (11,298 J m⁻³) < grass (26,410 J m⁻³) < tree (77,027 J m⁻³) < water body + tree (82,828 J m⁻³) < grass + tree (91,015 J m⁻³) < shading device (98,572 J m⁻³) < shading device + tree (102,069 J m⁻³), while the electric energy saving potential with regard to air conditioning follows the same order with the values of 9.108 × 10⁻³, 2.129 × 10⁻², 6.21 × 10⁻², 6.678 × 10⁻², 7.338 × 10⁻², 7.947 × 10⁻² and 8.229 × 10⁻² kWh m⁻³ respectively. The outcomes of this work provide practical information on the benefits of the urban green spaces for the decision makers and landscape designers.